Fernando Nunes da Silva

Conflict dissolution in the public sector: A case-study

Abstract The construction of a new railway link to the port of Lisbon has been postponed many times as a result of a conflict of different viewpoints held by various public stakeholders, namely between the municipality of Lisbon and the Lisbon Railway Node Bureau, while the Portuguese Railway Company has assumed a more flexible attitude. Over recent years, three groups of solutions, totalling nine alternative projects, have been proposed by each of these three actors, but none has been simultaneously accepted by all the three. The development of the urbanisation plan for Alcântara (the zone of the city where the railway line links to the port) has presented an opportunity to try to dissolve the conflict. This paper describes the multicriteria approach followed to support the creation of a new “good” (win–win) compromise solution by the planning team based on the study of the consequences of the existing alternatives. In particular, we describe the structuring phase of the study and the use of a disaggregation–aggregation approach to take into account the different value systems of the stakeholders.

Floodplain Management in Urban Developing Areas. Part II. GIS-Based Flood Analysis and Urban Growth Modelling

In Part I of this article the very dynamic nature of floodplain management was discussed and the need for modelling the urban growth processes and formulating scenarios of urban development was emphasised. In this second part, the use of Geographic Information Systems (GIS) for addressing those problems is presented. GIS have been recognised as a powerful means to integrate and analyse data from various sources in the context of comprehensive floodplain management. Adequate information and prediction capability is vital to evaluate alternative scenarios for flood mitigation policies and to improve decision making processes associated with flood management. A framework for the comprehensive evaluation of flood hazard management policies is also addressed in this article. This comprehensive approach to flood problems is more than an attitude or a philosophical starting point. It makes use of specific technological tools conceived to be used by different actors, some of them being nonexperts in flood analysis. These tools, based on GIS, are very appropriate for a participatory approach to flood policy formulation and floodplain management because they help communicating with the public in a scientifically correct and yet rather simple manner.

Floodplain Management in Urban Developing Areas. Part I. Urban Growth Scenarios and Land-Use Controls

Some of the most critical flood problems occur in urban areas where values at risk are higher and damages tend to be heavier. Fast urban developing regions raise very specific problems because of the unsteady situation of these regions in terms of catchment land-use and urban encroachment. A realistic approach to flood management in these situations requires the consideration of urban growth scenarios and the simulation of the corresponding flood conditions. Coastal towns are frequently located in floodplains and are subject to flood hazard. This is the case for many coastal areas in Southern Europe that are still developing fast due to migration of the population to these areas. In such cases, flood management cannot be dissociated from land-use management, and non-structural measures for flood control can play a crucial role. It is important to make an ex-post evaluation of these types of measures in areas where they have been adopted. These issues are addressed in two Portuguese catchments, representative of urban growth and related to flood problems in Portugal and other Southern European regions. The Laje catchment is used for the ex-post evaluation of nonstructural measures, and the Livramento catchment is used for the modelling of urban growth scenarios. Quantitative results and policy recommendations are presented based on these two case-studies. Floodplain management is better done with GIS, especially if it is linked to hydrologic and hydraulic modelling capabilities. The use of GIS for conducting these studies is presented in Part II of this article.

Single stage inverter for PV applications with One Cycle Sampling technique in the MPPT algorithm

This paper introduces a single-stage, single-phase, inverter, for maximum efficient photovoltaic grid connection. The inverter is based in a full-bridge converter where a few diodes and one inductor have been added to enable single stage operation. The new topology provides an additional buck-boost converter function at the bridge level in order to extract the maximum power from photovoltaic (PV) panel. Non linear control is used to regulate the sinusoidal current injected in the grid and the PV voltage, so that maximum power point tracker, MPPT, is obtained. The new MPPT algorithm uses one cycle sampling technique to obtain the average value of the voltage and current in the panel with a small time delay. This technique eliminates errors introduced in the MPPT calculation, due to the switching ripple. The proposed algorithm also allows the operation of the control circuit at a lower frequency than the high switching frequency of the bridge converter transistors.

Direct power control for Universal Power Flow Controller series converter

To maximize the power flow in a transmission grid while maintaining stability, unnatural power flows can be enforced by a Unified Power Flow Controller. Theoretically the control of active and reactive power flow can be without overshoot or cross coupling. Direct power control, based on instantaneous power theory, can apply the full potential of the power converter and achieve better results. Simulation is performed on a full 3 phase model with non-ideal transformers, series multilevel converter and load. Experiments on a 3 phase scaled model with multilevel converter are performed. Simulation results are confirmed by experimental results and demonstrate minimum control delay, no overshoot and no cross coupling. Direct power control is a valuable control technique for a UPFC, and the presented controller can be applied to voltage source converters. In this paper, the Direct Power Control is demonstrated in detail for a 3 level Neutral Point clamped inverter.

Bridgeless Single-Stage Full-Bridge Converter with One Cycle Control in the output voltage

This paper presents a bridgeless single-stage, single phase circuit topology consisting in the association of a full-bridge isolated DC-DC converter with only one input inductor connected to the grid and two rectifier diodes, to provide sinusoidal input current wave shaping. The use of a bridgeless input rectifier allows the proposed topology to present high efficiency, 91.7%. To avoid transformer saturation, One Cycle Control modulator - OCC - is used in the output voltage controller. Another particularity of this topology, not achieved in similar topologies, is the reduced zero input current cross distortion. The paper comprises the converter theoretical analysis, design criteria and experimental results of the input current and the output voltage obtained in a 500W prototype. The paper also includes the simulated and experimental dynamic responses of the input current and output voltage controllers.

Modelos de ordenamento em confronto na área metropolitana de Lisboa: cidade alargada ou recentragem metropolitana?

O artigo aborda os modelos de ordenamento territorial em confronto no processo de metropolizacao da regiao de Lisboa. Um, a partir do planeamento municipal, formaliza a cidade alargada. Outro, concebido a escala regional, aposta na cidade compacta. A execucao do modelo extensivo conduziu a uma estrutura de cidade distendida. Esta ocupacao, objecto de criticas, permanece activa, bem como os factores que a induzem, o que justifica as reticencias sobre a inversao de tendencias com uma expressao que signifique mudanca de paradigma. O modelo de contencao proposto pressupoe uma forte accao voluntarista da Administracao e um envolvimento empenhado dos municipios nessa estrategia, (ainda) nao salvaguardado. Por isso, identificam-se factores criticos na mudanca que importa controlar para caminhar no sentido da convergencia.

Douro Valley Tourism Plan

Purpose – The purpose of this paper is to demonstrate through a case study, how a tourist destination plan can contribute to the management of the destination, via the development of sustainable, coherent, integrated and efficient tourism actions.Design/methodology/approach – The methodology incorporates a literature review on tourism planning and a case study, where the models and tools presented are applied to the Douro Valley region.Findings – The Douro Valley Tourism Plan (DVTP) is based on an integrated and global perspective (by taking into consideration all the elements of the tourism system) and has been designed with the close and active involvement of the stakeholders. The goal is to ensure that all future actions will be pursued through a high commitment from the community and institutions of the region.Practical implications – Aware of the interest that the Portuguese Government has in the region, as well as the financial resources that can be deployed, attracting private investment and promot...

Power quality improvement of indirect matrix converter input currents using a small DC link filter

A new filter topology and control system to improve input current waveforms of Sparse Matrix Converters (SMC) is presented. The topology is based on an Indirect Sparse Matrix Converter fitted with input ac filter, aided by a small dc link 2nd order filter, with smaller parameters compared to the ac input filter. The control system is designed to regulate the input current and dc link capacitor voltage, with the objective of keeping constant the input id current component, while keeping the iq component close to zero, to obtain near unity input power factor. The filter design and control performance is validated by numerical simulations, and compared to a similar converter without the dc filter.

Distributed Adaptations to Traffic Quality Requirements

In this paper, we present DDQoS, or Distributed Dynamic Quality of Service, a novel architecture which uses QoS-configured routers as a support layer for a distributed approach on policy-based management system. The main purpose of this work is to model and test a distributed framework for globally (in a domain network) controlling QoS traffic classes parameters, in an effort to dynamically reach the best choice for QoS-conditioning parameters in each given situation, on all impacted routers of a network. The model proposed is available for use today, and does not require base changes in the existent network elements but only the configuration of the routers and the installation of some additional components in each one. The architecture answers the needs of adaptation in the network for the generality of multimedia traffic, when the performance of this traffic is threatened by the presence of flows with less strict requisites.