Oscar Lazaro

ITETRIS: a modular simulation platform for the large scale evaluation of cooperative ITS applications

Cooperative ITS systems are expected to improve road traffic safety and efficiency, and provide infotainment services on the move, through the dynamic exchange of messages between vehicles, and between vehicles and infrastructure nodes. The complexity of cooperative ITS systems and the interrelation between its components requires their extensive testing before deployment. The lack of simulation platforms capable to test, with high modelling accuracy, cooperative ITS systems and applications in large scale scenarios triggered the implementation of the EU-funded iTETRIS simulation platform. iTETRIS is a unique open source simulation platform characterized by a modular architecture that allows integrating two widely adopted traffic and wireless simulators, while supporting the implementation of cooperative ITS applications in a language-agnostic fashion. This paper presents in detail the iTETRIS simulation platform, and describes its architecture, standard compliant implementation, operation and new functionalities. Finally, the paper demonstrates iTETRIS large scale cooperative ITS evaluation capabilities through the implementation and evaluation of cooperative traffic congestion detection and bus lane management applications. The detailed description and implemented examples provide valuable information on how to use and exploit iTETRIS simulation potential.

A Hopfield neural-network-based dynamic channel allocation with handoff channel reservation control

As channel allocation schemes become more complex and computationally demanding in cellular radio networks, alternative computational models that provide the means for faster processing time are becoming the topic of research interest. These computational models include knowledge-based algorithms, neural networks, and stochastic search techniques. This paper is concerned with the application of a Hopfield (1982) neural network (HNN) to dynamic channel allocation (DCA) and extends previous work that reports the performance of HNN in terms of new call blocking probability. We further model and examine the effect on performance of traffic mobility and the consequent intercell call handoff, which, under increasing load, can force call terminations with an adverse impact on the quality of service (QoS). To maintain the overall QoS, it is important that forced call terminations be kept to a minimum. For an HNN-based DCA, we have therefore modified the underlying model by formulating a new energy function to account for the overall channel allocation optimization, not only for new calls but also for handoff channel allocation resulting from traffic mobility. That is, both new call blocking and handoff call blocking probabilities are applied as a joint performance estimator. We refer to the enhanced model as HNN-DCA++. We have also considered a variation of the original technique based on a simple handoff priority scheme, here referred to as HNN-DCA+. The two neural DCA schemes together with the original model are evaluated under traffic mobility and their performance compared in terms of new-call blocking and handoff-call dropping probabilities. Results show that the HNN-DCA++ model performs favorably due to its embedded control for assisting handoff channel allocation.

H.263 video traffic modelling for low bit rate wireless communications

Video traffic exhibits a greater complexity than traditional services such as voice. Therefore, it is necessary to identify the relevant statistical properties, which characterise this type of traffic and provide the tools to properly model them so that networks could be efficiently dimensioned. This work presents on one hand a detailed analysis of the statistical features, which characterise H.263 video traffic streams coded at bit rates suitable for wireless communications. On the other hand, the paper presents and evaluates an on-line video traffic model, which captures the most significant features observed.

An Innovative Virtual Enterprise Approach to Agile Micro and SME-Based Collaboration Networks

This paper demonstrates a lightweight and highly decentralized collaboration infrastructure approach for virtual enterprises and describes its added-value in the customer-oriented production domain. First, we will describe challenges and key requirements of an exemplary application scenario. Second, we are going to present the reference architecture and will explain the designs of enabling key concepts. Finally we highlight major improvements to the selected domain and the impact in economic, competition and social terms.

Enhanced multi-domain access control for secure mobile collaboration through Linked Data cloud in manufacturing

Collaborative networked organizations represent an important paradigm to help manufacturing companies to cope with the challenges of market turbulence. However, although manufacturing companies are increasingly aiming to implement mobile collaboration models, there are still some barriers that prevent manufacturers from effectively sharing big data leveraged in particular by the use of Internet of Things technologies. These barriers are basically related to the lack of security controls and lightweight data management enablers that would guarantee the protection of sensitive information published on the Linked Data cloud and leverage customers from the burden of linked data sharing. The aim of this paper is to present and discuss the industrial application of the necessary extensions to traditional role-based multi-domain access control approaches to enable secure and mobile collaboration among manufacturing enterprises in logistic, manufacturing and e-Commerce processes in the context of the Web of Data.

Dynamic channel allocation based on a Hopfield neural network and requirements for autonomous operation in a distributed environment

This paper presents a distributed architecture that provides a platform for performance study of cellular radio dynamic channel allocation (DCA) schemes based on a Hopfield neural network (HNN). HNN-based DCA schemes have been studied over the recent years but these techniques are invariably centralised. Operation in a distributed environment necessitates certain system level requirements for accessing system-wide channel allocation information used by the algorithm. Distributed operation also suggests that the HNN-based DCA schemes operate autonomously and it would be of interest to evaluate how such schemes compare with the centralised schemes. The paper describes a suitable network architecture for a distributed HNN and highlights some of its key benefits through simulation.

Integrated and Personalised Risk Management in the Sensing Enterprise

Due to its impact on economy, resources, environment and society, manufacturing is of strategic value to Europe. European manufacturing has to embrace a new logic of global socioeconomic sustainability, in which it addresses not only the welfare of its population, but also of emerging economies, contributing at the same time to the preservation of the environment and the resources. Megatrends that have a considerable impact on European manufacturing are:

Real-time generation of synthetic MPEG-4 video traffic using wavelets

This paper presents a wavelet-based video traffic model capable of real-time generation of synthetic MPEG-4 video traffic streams. The strength of the model includes a unified approach to LRD (long range dependence) and SRD (short range dependence) modelling, computational efficiency and benefits associated with the on-line aspect of the model, e.g. no storage requirements. The model accurately estimates system performance for every video quality considered.

ComVantage: Mobile Enterprise Collaboration Reference Framework and Enablers for Future Internet Information Interoperability

Future Internet Networked Enterprise Systems demand enhanced collaboration and mobility support. FI technologies are fundamental for increased service differentiation and cost optimisation in manufacturing environments. However, such ICT-based capabilities are not easy to introduce, in particular to SMEs, due to high costs and complexity. To progress in more effective development of value added services based on Web 2.0 principles within a mobile enterprise collaboration context, the complexity of collaboration in terms of information management needs to be leveraged from the end-users. Linked Data (LD) provides a universal and lightweight approach for the collaboration network. However, the elaboration of collaborative business processes based on LD still needs to be properly formulated for FI systems. The aim of this paper is to present a reference architecture for mobile enterprise collaboration based on LD interoperability. Moreover, security, semantic data lifting, business process modelling interoperability and mobile app orchestration enablers are presented to facilitate trustful and effective inter-organisational collaboration.

Statistical analysis and evaluation of modelling techniques for self-similar video source traffic

Video is expected to be a significant part of information in future mobile communication systems. An accurate and efficient video source traffic characterisation is therefore essential in order to assess new traffic handling algorithms and appropriately dimension the supporting communication networks. Modelling VBR traffic as a stochastic process is often challenging since such traffic exhibits the co-existence of long-term and short-term dependencies. To highlight such issues, in this paper, three video traffic-modelling techniques are presented and analysed in terms of first- and second-order statistics. A comparative evaluation of these models has been carried out based on simulation.