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- Velocity estimation of moving ships using C-band SLC SAR dataPublication . Radius, Andrea; Marques, PauloA new algorithm for the velocity vector estimation of moving ships using Single Look Complex (SLC) SAR data in strip map acquisition mode is proposed. The algorithm exploits both amplitude and phase information of the Doppler decompressed data spectrum, with the aim to estimate both the azimuth antenna pattern and the backscattering coefficient as function of the look angle. The antenna pattern estimation provides information about the target velocity; the backscattering coefficient can be used for vessel classification. The range velocity is retrieved in the slow time frequency domain by estimating the antenna pattern effects induced by the target motion, while the azimuth velocity is calculated by the estimated range velocity and the ship orientation. Finally, the algorithm is tested on simulated SAR SLC data.
- (Virtual) Agents for running electricity marketsPublication . Trigo, Paulo; Marques, Paulo; Coelho, HelderThis paper describes a multi-agent based simulation (MABS) framework to construct an artificial electric power market populated with learning agents. The artificial market, named TEMMAS (The Electricity Market Multi-Agent Simulator), explores the integration of two design constructs: (i) the specification of the environmental physical market properties and (ii) the specification of the decision-making (deliberative) and reactive agents. TEMMAS is materialized in an experimental setup involving distinct power generator companies that operate in the market and search for the trading strategies that best exploit their generating units' resources. The experimental results show a coherent market behavior that emerges from the overall simulated environment.
- Opportunity targets as references for phase correction on passive radar channelsPublication . Marques, PauloThis paper considers the problem of phase correction on Passive Radar using opportunity targets present in the target area. The proposed technique has very low hardware and computational requirements and can be applied to configurations where it is desirable, or necessary, to have dispersed receivers, such as in a multistatic passive radar system, avoiding the use of costly methods. The main idea is to take advantage of a reference target, with a known position, to correct the phase error on the several channels. Simulation results illustrating the effectiveness and limitations of the proposed methodology are presented.
- Low-carbon cement with waste oil-cracking catalyst incorporationPublication . Costa, Carla; Marques, PauloThe present paper shows preliminary results of an ongoing project which one of the goals is to investigate the viability of using waste FCC catalyst (wFCC), originated from Portuguese oil refinery, to produce low carbon blended cements. For this purpose, four blended cements were produced by substituting cement CEM I 42.5R up to 20% (w/w) by waste FCC catalyst. Initial and final setting times, consistency of standard paste, soundness and compressive strengths after 2, 7 and 28 days were measured. It was observed that the wFCC blended cements developed similar strength, at 28 days, compared to the reference cement, CEM I 42.5R. Moreover, cements with waste FCC catalyst incorporation up to 15% w/w meet European Standard EN 197-1 specifications for CEM II/A type cement, in the 42.5R strength class.
- Improved detection for passive radar by illumination matching on reference channelPublication . Marques, PauloA novel technique for enhancing the detection of targets of interest is presented for application on the context of passive radar. The methodology is inspired on the well known Matched Illumination technique used in active systems and applies to scenarios where the targets can be modeled as having a few predominant scatterers. Since passive systems have no control over the signals which are transmitted by the illuminators of opportunity, the paper proposes to match the signal received on the reference channel. Results show that the correlation function will be enhanced for the targets of interest, relatively to the remaining targets and the clutter on the target region.
- Phase correction for passive radar using targets of opportunityPublication . Marques, PauloThis paper presents a novel phase correction technique for Passive Radar which uses targets of opportunity present in the target area as references. The proposed methodology is quite simple and enables the use of low cost hardware with independent oscillators for the reference and surveillance channels which can be geographically distributed. © 2014 IEEE.
- Multi-agent simulation of electricity markets economically-motivated decision-makingPublication . Trigo, Paulo; Sousa, Jorge A. M.; Marques, PauloThe key motivation for this research is the perception that within a near future the electricity market will be composed of individuals that may simultaneously undertake the roles of consumers, producers and traders of electricity. Those individuals are economically motivated “prosumer” (producer-consumer) agents that not only consume, but can also produce, store and trade electricity. Therefore, as the prosumer agents follow their economically motivated goals (e.g., aiming for profit) they will also experience different forms of power (e.g., market power) and their social relations (e.g., dependencies) will mutually influence their decisionmaking processes. This paper describes the most relevant aspects of a simulation tool that provides (human and virtual) prosumer agents na interactive and real-time game-like environment where they can explore (long-term and short-term) strategic behaviour and experience the effects of power and social influence in their decisionmaking processes. The work on the quantitative description of power and influence concepts, is described and details are provided throughout an illustrative example.
- Noise Radar Detection Optimized for Selected TargetsPublication . Marques, PauloThis paper presents a technique for detection of selected targets in the context of ultrawideband noise radar. The technique applies to scenarios where targets can be modeled as having a few predominant scatterers, such as some made man-made targets. The basic idea is to change the signal used as reference for detection in such a way that it is adapted to the predominant scatterers of the targets. When compared with another recently published technique the obtained detection gains are similar. However, in contrast to that, the proposed technique shows the additional advantage that the received data is still useful for further processing.
- An SEM investigation of the pozzolanic activity of a waste catalyst oil refineryPublication . Costa, Carla; Marques, Paulo; Carvalho, P. A.The most active phase of the fluid catalytic cracking (FCC) catalyst, used in oil refinery, is zeolite-Y which is an aluminosilicate with a high internal and external surface area responsible for its high reactivity. Waste FCC catalyst is potentially able to be reused in cement-based materials - as an additive - undergoing a pozzolanic reaction with calcium hydroxide (Ca(OH)2) formed during cement hydration [1-3]. This reaction produces additional strength-providing reaction products i.e., calcium silicate hydrate (C-S-H) and hydrous calcium aluminates (C-A-H) which exact chemical formula and structure are still unknown. Partial replacement of cement by waste FCC catalyst has two key advantages: (1) lowering of cement production with the associated pollution reduction as this industry represents one of the largest sources of man-made CO2 emissions, and (2) improving the mechanical properties and durability of cement-based materials. Despite these advantages, there is a lack of fundamental knowledge on pozzolanic reaction mechanisms as well as spatial distribution of porosity and solid phases interactions at the microstructural level and consequently their relationship with macroscopical engineering properties of catalyst/cement blends. Within this scope, backscattered electron (BSE) images acquired in a scanning electron microscope (SEM) equipped with Energy-Dispersive Spectroscopy (EDS) and by X-ray diffraction were used to investigate chemical composition of hydration products and to analyse spatial information of the microstructure of waste FCC catalyst blended cement mortars. For this purpose mortars with different levels of cement substitution by waste catalyst as well as with different hydration ages, were prepared. The waste FCC catalyst used is produced by the Portuguese refinery company Petrogal S.A.