Gladys Diaz

A Comparative Study of Policy Specification Languages for Secure Distributed Applications

This paper presents a comparative study of policy specification languages. Our objective is to find policy language or notation that is the most suitable to express the security aspects of distributed applications running on policy-based networks. We first made a selection of languages and we compare them on several criteria: their suitability to specify security, their ability to express both user and network oriented security aspects, the representation technique they use and the notions they are able to express. This paper concludes on a discussion on what would be the ideal policy language for distributed applications that have strong security constraints.

Policy-Based Quality of Service and Security Management for Multimedia Services on IP Networks in the RTIPA Project

This paper summarizes the research work that has been conducted in the context of the RTIPA project on policy-based QoS (Quality of Service) and security management for distributed multimedia services. It presents an architecture allowing the derivation of policies from the service level down to the network level. It is a step towards an end-to-end QoS and security management for distributed multimedia services running on the new generation of IP networks.

Virtual police agents for ITS traffic routing

Delays and traffic bottlenecks represent a significant economic loss and inconvenient issues in transportation of persons and goods. That is, transportation systems still have a wide spectrum of issues that need to be addressed. In this sense, Intelligent Transportation Systems (ITS) are expected to provide an efficient and modern way to deal with these issues. Nevertheless, underlying technologies are not always reachable for urban settlements with budget restraint such as in rural areas and in developing countries. In this paper, we present a novel and affordable architecture aiming to improve vehicular traffic management based on intelligent Virtual Police Agents (VPA). Our architecture is inspired from real police agents figure which are oriented to manage traffic issues efficiently. The replication of basic features of police agent role in VPA results in collaborative and hierarchical agent-based relationship architecture. This framework aims to establish system-optimal based in traffic flow equilibrium with maximum-flow and minimum-cost.

Modeling Data to Management Dynamic Services Deployment in Autonomic Networks

One of the biggest challenges of the Internet Service Provider actually is the ability to deploy dynamically new services. For this purpose, in this paper, we are interested in the specification and modeling of different notions in the context of autonomic networks, in order to dynamically deploy new network services. Thus, we propose in this work a new object-oriented information model to represent the network state and facilitate the service introduction. Within this model we propose the concept of service profile and deployment profile. The service profiles identify one possible configuration of service, and the deployment profiles identify a client service request. Our information model is representing by using UML.

How Virtual Police Agents can help in the traffic guidance

Nowadays transportation systems suffer from many adversities. One of the most notorious issues is the traffic congestion. The transportation of persons and goods experiment notable delays with the consequent waste of precious resources and the rise of pollution. Actual Intelligent Transportation systems (ITS) are intended to relief the broad spectrum of challenges that affect our modern traffic infrastructures. However the deployment of these technologies is not always reachable for all cities. Also this is not always fully implemented because of the heavy infrastructure required and the elevated cost. In this paper we assess an architecture based on traffic routing services. This is a lighter implementation and affordable cost for cities where ITS technologies are scarce or absent such as cities in developing countries. In this paper we evaluate how our architecture called Virtual Police Agent for ITS traffic Routing [1], [2] can help to improve the traffic performance. The end of this paper is to evaluate the benefits of Virtual Police Agents by means of several proposed scenarios.

Use case description of VPAIR: Virtual Police Agents for traffic guidance

Nowadays the traffic systems for the transportation of goods and persons is an important subject that affects our economies, social interactions and almost every aspect of our life. Delays and traffic bottlenecks represent a significant inconvenient and problematic in this area. The ITS architectures provides innovative solutions to solve many aspect of this problematic. However these solutions tend to be heavy in infrastructure and costly in implementation and maintenance. Our approach is oriented to traffic guidance systems with light infrastructure and affordable cost to be implemented over urban networks where budget is a vital constraint such as rural areas and developing countries. We present in this paper the typical use case of our solution for traffic routing services. We call our general architecture VPAIR (Virtual Police Agent for ITS Traffic Routing). The objective pursued is to affect the driver decision in such a way as to maintain a fairness System-Optimal.

ITS forecast: GIS integration with active sensory system

In the context of Intelligent Transport Systems (ITS) the monitoring and forecast of transportation systems is a common and recurrent necessity. As long as transport networks increment constantly their size and complexity there are new requirement for traffic prediction, routing calculation and congestion/accident avoidance.

An integrated ITS framework for traffic forecast with GIS and active sensory assistance

Herein we present an ITS framework to provide timely and accurate ITS forecast with the assistance of GIS (Geographic Information System) and an active sensory system. Urban settlements can be viewed as a collection of street regulators acting like points of flow control. Cars are affected in their travel performance when queuing up through these traffic controllers. These flow regulators can be defined as an integrated system of interconnected models distributed all over the urban environment. The objective is to regulate the traffic flow in a fast and secure way. We propose in this paper an approach to integrate a GIS with an active sensory system in order to provide timely and accurate ITS forecast. Our efforts are oriented to predict accurate short-term traffic conditions and reliable long-term traffic forecast with the support of available ITS technologies.

Performance evaluation and comparative study of main VDTN routing protocols under small- and large-scale scenarios

Abstract This paper presents a performance evaluation through simulations and a comparative study of main routing protocols dedicated to Vehicular Delay-Tolerant Networks. The assessment is conducted under small- and large-scale scenarios with realistic vehicle mobility patterns as defined in the TAPAS Cologne simulation scenario. Through the literature, several evaluations have been conducted on routing for Vehicular Networks, but with an abstraction or a simplification regarding the delay tolerant aspect. Furthermore, considered scenarios were relatively small and too idealistic compared to the real-world environment and its multiples challenges. Moreover, to the best of our knowledge, this is the first extensive study that compares, in the same realistic simulation environment, the main flag-carriers of various categories of VDTN routing protocols, namely Epidemic, Direct Delivery, Prophet and GeoSpray protocols. Simulation results reveal better performance for the geographical approach advocated by GeoSpray compared to the predictive one of Prophet, under all considered scenarios. Moreover, they highlight the possibility for a minimalist and naive protocol such as Direct Delivery to perform well, under specific network conditions, as when considering an anycast communication scheme. Finally, deeper analysis was undertaken on both GeoSpray and Prophet. The studies reveal the potentialities to increase the performances of GeoSpray to some extent and highlight the difficulties of adapting Prophet settings for optimal performance in realistic scenarios.

Adaptive Contention Window for Zone-Based Dissemination of Vehicular Traffic

Inter-Vehicular Communication (IVC) is very promising for advanced applications in traffic systems. However, current efforts and implementations still require more attention in order to turn such applications into reality. The data dissemination and the vehicular communication are two key concerns in order to make more feasible alternative traffic information systems. In this paper we focus on the traffic data dissemination and the inter-vehicle communication applied to our traffic guidance architecture presented in [5]. We present a twofold proposal: a mechanism for V2I, V2V traffic data dissemination and a simple but efficient mechanism to enhance broadcast communication. We show through extensive evaluations that our composite solution tends to be efficient under the design of our specific application guidelines.