Repositório IC-Online

Institution's Scientific Repository

IC-Online, the Institutional Repository of Scientific Information of the Polytechnic of Leiria (IPLeiria), is part of the RCAAP Project (Open Access Scientific Repositories of Portugal). Its main objectives are to organise, preserve and disseminate the scientific production of the Polytechnic of Leiria (IPLeiria), helping to increase the visibility and impact of the institution's scientific publications.

The IC-Online Repository includes various types of digital documents, such as articles from national and international scientific journals, papers from congresses and conferences, master's dissertations and doctoral theses, among others.

Política Institucional de Acesso Livre do Politécnico de Leiria (Despacho nº 124/2018)
Regras de afiliação do Politécnico de Leiria (Despacho nº 228/2020)
Normas de atribuição de identificadores DOI, ISBN e DL (Despacho nº 257/2024)
Apoio à investigação

Email repositorio@ipleiria.pt

Recent Submissions

Tunable Immune Detectors for Behaviour-Based Network Intrusion Detection

Publication . Antunes, Mário; Correia, Manuel E.

Computer networks are highly dynamic environments in which the meaning of normal and anomalous behaviours can drift considerably throughout time. Behaviour-based Network Intrusion Detection System (NIDS) have thus to cope with the temporal normality drift intrinsic on computer networks, by tuning adaptively its level of response, in order to be able to distinguish harmful from harmless network traffic flows. In this paper we put forward the intrinsic Tunable Activation Threshold (TAT) theory ability to adaptively tolerate normal drifting network traffic flows. This is embodied on the TAT-NIDS, a TAT-based Artificial Immune System (AIS) we have developed for network intrusion detection. We describe the generic AIS framework we have developed to assemble TAT-NIDS and present the results obtained thus far on processing real network traffic data sets. We also compare the performance obtained by TAT-NIDS with the well known and widely deployed signature-based snort network intrusion detection system.

2011Conference object

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Adaptive coding tree for complexity control of high efficiency video encoders

Publication . Correa, G.; Assunção, P.; Silva Cruz, L. A. da; Agostini, L.

The emerging HEVC standard introduces several techniques which increase compression efficiency in comparison to its predecessors. However, such advances are accompanied by increases in computational complexity, limiting the encoder use in computational or power-constrained devices. This paper proposes a novel complexity control method for the future HEVC encoders based on a dynamic adjustment of the newly proposed coding tree structures. The relationship between coding tree depths and the encoding complexity is explored to selectively constrain encoding possibilities in order to not exceed a predefined complexity target. Experimental results show that the encoder computational complexity can be downscaled to 60% with a bit rate increase under 3.5% and a PSNR decrease under 0.1 dB.

2012-05Conference paper

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A 130 nm CMOS LNA for 30 GHz applications

Publication . Ribeiro, R.; Moreira Mendes, Luís Miguel; Vaz, J. C.; Rosario, M. J.; Freire, J. C.

This paper presents the design of a 30 GHz low noise amplifier in a 130 nm CMOS technology. The amplifier is based on a cascode topology. The circuit uses autotransformers in the input and output matching networks. This design approach eliminates the necessity of the use of source degeneration and allows obtaining an ultra compact LNA. The amplifier presents a forward gain (S21) of 7.4 dB at 30 GHz with a bandwidth of 10 GHz, input and output VSWRs better than 1.22:1 and a noise figure of 3.7 dB. The LNA is unconditionally stable and consumes only 7 mW when supplied with 1.2 V. The amplifier fits an area of 0.08 mm2, which is one of the smallest areas reported.

2011-04Conference paper

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Religião: património cultural e artístico na afirmação identitária do Reguengo do Fetal - Portugal

Publication . Magalhães, Fernando; Vicente, José

Introdução: Os resultados apresentados neste texto são fruto de uma investigação sobre a aldeia portuguesa Reguengo do Fetal, o seu património cultural e a construção da sua identidade local. Esta aldeia, localizada no concelho da Batalha, é conhecida em Portugal pela Romaria em honra de Nossa Senhora do Fetal e pelas Procissões de Caracóis. Metodologia: A investigação baseou-se num trabalho de campo com observação participante, em sentido lato, para estudar o património cultural local e as estratégias de apropriação do mesmo. O foco foi a forma como este património contribui para a construção de sentimentos de pertença num contexto globalizado. Resultados: Identificou-se que, tal como noutras comunidades católicas, como Fátima, a vida religiosa em Reguengo do Fetal, centrada na aparição da Virgem Maria, é uma componente fundamental das vivências culturais locais. O milagre atribuído à Virgem é a base do importante património cultural, material e imaterial, da comunidade. Discussão: Este património marca os lugares de memória mais importantes para os habitantes do Reguengo do Fetal e analisou-se como as estratégias de apropriação cultural contribuem para a afirmação de um sentimento de pertença no mundo globalizado. Conclusões: O estudo deste património cultural local permite perceber como as comunidades mantêm a sua identidade e ligação ao passado num contexto de globalização.

2025-01-30Journal article

Open access

Performance metrics for evaluation of a mixed measurement based state estimator

Publication . Vide, P. Castro; Barbosa, F. Maciel; Carvalho, J. Beleza

With the development of synchronized phasor measurement technology in recent years, it gains great interest the use of PMU measurements to improve state estimation performances. In this paper, a mixed measurement (SCADA and PMU measurements) state estimator is proposed. Several measures useful for evaluating various aspects of the performance of the mixed measurement state estimator are proposed and explained. State Estimator validity, performance and characteristics of the results on IEEE 14 bus test system are presented.

2012-05Conference paper

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