Complex networks as an emerging property of hierarchical preferential attachment

Real complex systems are not rigidly structured; no clear rules or blueprints exist for their construction. Yet, amidst their apparent randomness, complex structural properties universally emerge. We propose that an important class of complex systems can be modeled as an organization of many embedded levels (potentially infinite in number), all of them following the same universal growth principle known as preferential attachment. We give examples of such hierarchy in real systems, for instance in the pyramid of production entities of the film industry. More importantly, we show how real complex networks can be interpreted as a projection of our model, from which their scale independence, their clustering, their hierarchy, their fractality and their navigability naturally emerge. Our results suggest that complex networks, viewed as growing systems, can be quite simple, and that the apparent complexity of their structure is largely a reflection of their unobserved hierarchical nature.Comment: 12 pages, 7 figure

Phase transition of the susceptible-infected-susceptible dynamics on time-varying configuration model networks

We present a degree-based theoretical framework to study the susceptible-infected-susceptible (SIS) dynamics on time-varying (rewired) configuration model networks. Using this framework, we provide a detailed analysis of the stationary state that covers, for a given structure, every dynamic regimes easily tuned by the rewiring rate. This analysis is suitable for the characterization of the phase transition and leads to three main contributions. (i) We obtain a self-consistent expression for the absorbing-state threshold, able to capture both collective and hub activation. (ii) We recover the predictions of a number of existing approaches as limiting cases of our analysis, providing thereby a unifying point of view for the SIS dynamics on random networks. (iii) We reinterpret the concept of hub-dominated phase transition. Within our framework, it appears as a heterogeneous critical phenomenon : observables for different degree classes have a different scaling with the infection rate. This leads to the successive activation of the degree classes beyond the epidemic threshold.Comment: 14 pages, 11 figure

Creating Context-Adaptive Business Processes

Acceptance rate : 15%, Rank (CORE) : AInternational audienceAs the dynamicity of today's business environments keeps increasing, there is a need to continuously adapt business processes in order to respond to the changes in those environments and keep a competitive level. By using complex event processing, we can discover information that is relevant to our organization, which is usually hidden among the data generated in the environment, and use it to adapt the processes accordingly in order to respond to the changing conditions in an optimal way. Unfortunately, the static nature of business process definitions makes it impossible to adapt them at runtime and the redeployment of a modified process is required. By using a component-based approach, we can transform the existing business processes into dynamically bound components, adding the flexibility needed to adapt the processes at runtime. In this paper we present CEVICHE, a framework that combines the strengths of complex event processing and dynamic business process adaptation, which allows to respond to the needs of the rapidly changing environment, and its adaptation language called SBPL, an extension to BPEL which adds flexibility to business processes

AProSec: an Aspect for Programming Secure Web Applications

International audienceAdding security functions in existing Web application servers is now vital for the IS of companies and organizations. Writing crosscutting functions in complex software should take advantage of the modularity offered by new software development approaches. With Aspect-Oriented Programming (AOP), separating concerns when designing an application fosters reuse, parameterization and maintenance. In this paper, we design a security aspect called AProSec for detecting SQL injection and Cross Scripting Site (XSS) that are common attacks in web servers. We experiment this aspect with the AspectJ language and the JBoss AOP framework. With this experimentation, we show the advantage of runtime platforms such as JBoss AOP for changing security policies at runtime. Finally, we describe related work on security and AOP

QoS Contract-Aware Reconfiguration of Component Architectures Using E-Graphs

International audienceIn this paper we focus on the formalization of component-based architecture self-reconfiguration as an action associated to quality-of-service (QoS) contracts violation. With this, we aim to develop on the vision of the component-based software engineering (CBSE) as a generator of software artifacts responsible for QoS contracts. This formalization, together with a definition of a QoS contract, forms the basis of the framework we propose to enable a system to preserve its QoS contracts. Our approach is built on a theory of extended graph (e-graph) rewriting as a formalism to represent QoS contracts, component-based architectural structures and architecture reconfiguration. We use a rule-based strategy for the extensible part of our framework. The reconfiguration rules are expressed as e-graph rewriting rules whose left and right hand sides can be used to encode design patterns for addressing QoS properties. These rules, given by a QoS property domain expert, are checked as safe, i.e., terminating and confluent, before its application by graph pattern-matching over the runtime representation of the system

Termination Mechanisms of Turing Patterns in Growing Systems

International audienceThe question of the termination of a periodic spatial structure of Turing type in a growing system is addressed in a chemical engineering perspective and a biomimetic approach. The effects of the dynamical parameters on the stability and the wavelength of the structure are analytically studied and used to propose experimental conditions for which a Turing pattern stops by itself with a decreasing wavelength. The proposed mechanism is successfully checked by the numerical integration of the equations governing the dynamics of the activator and the inhibitor. We conclude that a local increase of the concentration of the reservoir which controls the injection rate of the inhibitor into the system can be used to achieve the appropriate termination of a Turing pattern

A Traceability Service to Facilitate RFID Adoption in the Retail Supply Chain

ISBN: 978-989-8111-94-4International audienceNowadays, companies are suffering changes in the way they deal with their inventories and their whole supply chain management. New technologies are emerging to help them adapt to the changes and keep a competitive status, but the adoption of such technologies is not always easy. Even though a lot of research has been done for RFID, there are still some areas that are being left aside, like the traceability aspect, which is one of the most important concerns in the retail supply chain. We propose a service named TRASER (TRAceability SErvice for the Retail supply chain) that will help the companies adopt the new technologies into their existing environments, dealing with persistence and traceability, and allowing the users to manage their operation according to their business rules, workflows and historical data

Unusual Radiographic Presentation of Pneumocystis Pneumonia in a Patient with AIDS.

Pneumocystis jirovecii pneumonia (PCP) typically presents as an interstitial and alveolar process with ground glass opacities on chest computed tomography (CT). The absence of ground glass opacities on chest CT is thought to have a high negative predictive value for PCP in individuals with AIDS. Here, we report a case of PCP in a man with AIDS who presented to our hospital with subacute shortness of breath and a nonproductive cough. While his chest CT revealed diffuse nodular rather than ground glass opacities, bronchoscopy with bronchoalveolar lavage and transbronchial biopsies confirmed the diagnosis of PCP and did not identify additional pathogens. PCP was not the expected diagnosis based on chest CT, but it otherwise fit well with the patient's clinical and laboratory presentation. In the era of combination antiretroviral therapy, routine prophylaxis for PCP, and increased use of computed tomography, it may be that PCP will increasingly present with nonclassical chest radiographic patterns. Clinicians should be aware of this presentation when selecting diagnostic and management strategies

A Framework for Evaluating Quality-Driven Self-Adaptive Software Systems

International audienceOver the past decade the dynamic capabilities of self-adaptive software-intensive systems have proliferated and improved significantly. To advance the field of self-adaptive and self-managing systems further and to leverage the benefits of self-adaptation, we need to develop methods and tools to assess and possibly certify adaptation properties of self-adaptive systems, not only at design time but also, and especially, at run-time. In this paper we propose a framework for evaluating quality-driven self-adaptive software systems. Our framework is based on a survey of self-adaptive system papers and a set of adaptation properties derived from control theory properties. We also establish a mapping between these properties and software quality attributes. Thus, corresponding software quality metrics can then be used to assess adaptation properties