Conflicts treatment for ubiquitous collective and context-aware applications

Context-aware computing is a research field that defines systems capable of adapting their behavior according to any relevant information about entities (e.g., people, places and objects) of interest. The ubiquitous computing is closely related to the use of contexts, since it aims to provide personalized, transparent and on-demand services. Ubiquitous systems are frequently shared among multiple users, which may lead to conflicts that occur during adaptation actions due to individual profiles divergences and/or environment resources incompatibility. In such situations it is interesting to detect and solve those conflicts, considering what is better for the group but also being fair enough with each individual demand, whenever possible. This work presents the important concepts on the collective ubiquitous context-aware applications field. Furthermore, it proposes a novel methodology for conflicts detection and resolution that considers the trade-off between quality of services and resources consumption. A case study based on a collective tourist guide was implemented as a proof-of-study to the proposed methodology.Key words: context and awareness in collaborative systems, ubiquitous computing, adaptive collaborative environments

CReMe: a Dynamic and Flexible Conflict Resolution Methodology for Competitive Ambient Systems

AbstractAmbient Systems are available to their users all the time and everywhere. Most of them can be viewed as collective applications, i.e., shared by two or more users, which may lead to competition for resources and personal needs, generating conflicts of interests. The goal of this work is to present CReMe, a dynamic and flexible methodology to detect and solve conflicts for ambient systems. Two distinct case studies were evaluated to demonstrate CReMe's characteristics. The results showed that it was possible to accomplish a tradeoff between computational resources consumption and users’ satisfaction

Structural Properties of the Brazilian Air Transportation Network

The air transportation network in a country has a great impact on the local, national and global economy. In this paper, we analyze the air transportation network in Brazil with complex network features to better understand its characteristics. In our analysis, we built networks composed either by national or by international flights. We also consider the network when both types of flights are put together. Interesting conclusions emerge from our analysis. For instance, Viracopos Airport (Campinas City) is the most central and connected airport on the national flights network. Any operational problem in this airport separates the Brazilian national network into six distinct subnetworks. Moreover, the Brazilian air transportation network exhibits small world characteristics and national connections network follows a power law distribution. Therefore, our analysis sheds light on the current Brazilian air transportation infrastructure, bringing a novel understanding that may help face the recent fast growth in the usage of the Brazilian transport network

Decentralized Intrusion Detection in Wireless Sensor Networks

Wireless sensor networks (WSNs) have many potential applications. Furthermore, in many scenarios WSNs are of interest to adversaries and they become susceptible to some types of attacks since they are deployed in open and unprotected environments and are constituted of cheap small devices. Preventive mechanisms can be applied to protect WSNs against some types of attacks. However, there are some attacks for which there is no known prevention methods. For these cases, it is necessary to use some mechanism of intrusion detection. Besides preventing the intruder from causing damages to the network, the intrusion detection system (IDS) can acquire information related to the attack techniques, helping in the development of prevention systems. In this work we propose an IDS that fits the demands and restrictions of WSNs. Simulation results reveal that the proposed IDS is efficient and accurate in detecting different kinds of simulated attacks