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Publications

2015

DCRP: a scalable path selection and forwarding scheme for IEEE 802.11s wireless mesh networks

Authors
Sampaio, S; Souto, P; Vasques, F;

Publication
EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING

Abstract
The IEEE 802.11s standard specifies a mesh technology to be supported by IEEE 802.11 devices. Among the limitations caused by this heritage, we focus on the low scalability of the current IEEE 802.11s standard mechanisms. As a main contribution to the related research field, this article presents the DHT-based Cluster Routing Protocol (DCRP). DCRP addresses IEEE 802.11s' scalability issues by exploiting both Distributed Hash Tables and Clustering schemes, which have proved to be effective in scaling wireless (e.g., MANETs) and wired (e.g., P2P) networking systems. DCRP was implemented and compared with the HWMP through simulation for different scalability parameters and performance metrics. Simulation results indicate that the proposed scheme improves performance in terms of packet delivery ratio, end-to-end delay, throughput, and overhead.

2015

Reliability metrics for the evaluation of the schedule plan in public transportation

Authors
Sousa, JFd; Mendes-Moreira, J; Moreira-Matias, L; Gama, J;

Publication
Assessment methodologies: energy, mobility and other real world application

Abstract

2015

Context-aware, accessibility and dynamic adaptation of mobile interfaces in business environments

Authors
Sousa, A; Barroso, J; Paredes, H; Fernandes, H; Filipe, V;

Publication
PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON SOFTWARE DEVELOPMENT AND TECHNOLOGIES FOR ENHANCING ACCESSIBILITY AND FIGHTING INFO-EXCLUSION

Abstract
Technology entered in our lives and changed not only the way we communicate and interact with each other, but also our habits and the experiences in the real and digital worlds. However, due to the rapid progress, we use technology in every moment of our day and sometimes this causes some frustration because the way we interact with the applications is not the most effective for the context we are in. This problem is even more significant in the business environments, where effectively the time we take to finish some kind of task can mean profit or loss for the business. The key to these problems can be in the adaptation of the interface to user needs and constrains as it happens in solutions for situational induced impairment and disabilities (SIID). This can be made by inference the context in which the user it is by using different sensors available on mobile platform and different sources of information such as user profile, agenda and usage history. In this paper we propose a review of the main challenges of the dynamic adaptation of interfaces, with a case of application in a business environment. (c) 2015 The Authors. Published by Elsevier B.V.

2015

A conjectural supply function equilibrium in energy and reserve for a weekly horizon

Authors
González, P; Villar, J; Díaz, C; Campos, FA;

Publication
International Conference on the European Energy Market, EEM

Abstract
Despite the fact that reserves still have a small impact on the final electricity price, the rapid irruption of renewable and interruptible technologies has put in the spotlight the value of these services. It seems therefore important to rely on market models able to output realistic energy and reserve prices under imperfect competition. However, few are the authors that have modeled strategic behavior in both commodities. This paper presents an hourly multi-period oligopolistic model for energy and reserve markets, with units' commitment decisions and hydro-coordination, based on the conjectural supply function equilibrium. Its outputs have been compared with real Spanish data from the first weeks of 2011 with satisfactory results. © 2015 IEEE.

2015

Routing Protocols for IEEE 802.11-Based Mesh Networks

Authors
Sampaio, S; Vasques, F;

Publication
- Encyclopedia of Information Science and Technology, Third Edition

Abstract

2015

An evolutionary multi-objective optimization system for earthworks

Authors
Parente, M; Cortez, P; Gomes Correia, AG;

Publication
EXPERT SYSTEMS WITH APPLICATIONS

Abstract
Earthworks involve the leveling or shaping of a target area through the moving or processing of the ground surface. Most construction projects require earthworks, which are heavily dependent on mechanical equipment (e.g., excavators, trucks and compactors). Often, earthworks are the most costly and time-consuming component of infrastructure constructions (e.g., road, railway and airports) and current pressure for higher productivity and safety highlights the need to optimize earthworks, which is a non-trivial task. Most previous attempts at tackling this problem focus on single-objective optimization of partial processes or aspects of earthworks, overlooking the advantages of a multi-objective and global optimization. This work describes a novel optimization system based on an evolutionary multi-objective approach, capable of globally optimizing several objectives simultaneously and dynamically. The proposed system views an earthwork construction as a production line, where the goal is to optimize resources under two crucial criteria (costs and duration) and focus the evolutionary search (non-dominated sorting genetic algorithm-II) on compaction allocation, using linear programming to distribute the remaining equipment (e.g., excavators). Several experiments were held using real-world data from a Portuguese construction site, showing that the proposed system is quite competitive when compared with current manual earthwork equipment allocation.

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