2008
Authors
Luo, Q; Salgado, HM; Moura, AM; Pereira, JR;
Publication
2008 Loughborough Antennas and Propagation Conference, LAPC
Abstract
This work studies dual-band EBG structures used as an Artificial Magnetic Conductor (AMC) ground plane for WLAN co-planar antenna to achieve a low profile structure. From the simulation results, the EBG surface geometry with Jerusalem Cross (JCSS) slot has been chosen in this study. A dual band prototype operating at 2.4 and 5.2 GHz has been implemented and tested. The results show that the EBG antenna can work properly at desired frequency bands with improved gain and reduced back lobe. ©2008 IEEE.
2008
Authors
Pessoa, LM; Salgado, HM; Darwazeh, I;
Publication
2008 DIGEST OF THE LEOS SUMMER TOPICAL MEETINGS
Abstract
The electrical compensation of chromatic dispersion (CD) and polarization mode dispersion (PMD) in a coherent optical system exploiting polarization multiplexing is discussed in this paper. The benefits of combining a phase estimation algorithm with a decision directed least-mean-square equalizer in a feedback configuration is reported.
2008
Authors
Oliveira, JMB; Rodrigues, MRD; Salgado, HM;
Publication
2008 IEEE INTERNATIONAL CONFERENCE ON ULTRA-WIDEBAND, VOL 2, PROCEEDINGS
Abstract
In this paper, we study the effect of uplink wise on the optimality of the receiver structure proposed in [1][2]. This optimum receiver is composed by a demodulator that extracts a set of sufficient statistic, and by an ML detector that uses the demodulator output to estimate the original data, We concentrate on Intensity Modulation/Direct Detection (IM/DD) Radio-over-Fiber (RoF) uplink system when OFDM signals suffer from noise generated by the antenna and photodiode and from nonlinear distortion. The results show that for small and medium modulalion index values, the uplink noise maintains its Gaussian distribution and the optimum receiver still outperforms the conventional.
2008
Authors
Timmerer, C; Ransburg, M; Kofler, I; Hellwagner, H; Souto, P; Andrade, MT; Carvalho, P; Castro, H; Sidibé, M; Mehaoua, A; Fang, L; Lindsay, A; Mackay, M; Lugmayr, A; Feiten, B;
Publication
4th International ICST Mobile Multimedia Communications Conference, MOBIMEDIA 2008, Oulu, Finland, July 7-9, 2008
Abstract
2008
Authors
Timmerer, C; Rogai, D; Andrade, MT; Carvalho, P; Cordara, G;
Publication
MM 2008 - Proceedings of the 2008 ACM International Conference on Multimedia, with Co-located Symposium and Workshops: MS 2008
Abstract
The MPEG-21 standard forms a comprehensive multimedia framework covering the entire multimedia distribution chain. In particular, it provides a flexible approach to represent, process, and transact complex multimedia objects which are referred to as Digital Items (DIs). DIs can be quite generic, independent of the application domain, and can encompass a diversity of media resources and metadata. This flexibility has an impact on the level of interoperability between systems and applications, since not all the functionality needs to be implemented. Furthermore, additional semantic rules may be implemented through the processing of the Digital Item which is possibly driven by proprietary metadata. This jeopardizes interoperability and consequently raises barriers to the successful achievement of augmented and transparent use of multimedia resources. In this context, we have investigated and evaluated the interoperability at the semantic level of Digital Items throughout the automated production, delivery and consumption of complex multimedia resources in heterogeneous environments. This paper describes the studies conducted, the experiments performed, and the conclusions reached towards that goal. © Copyright 2008 ACM.
2008
Authors
Shao, BL; Mattavelli, M; Renzi, D; Andrade, MT; Battista, S; Keller, S; Ciobanu, G; Carvalho, P;
Publication
2008 IEEE INTERNATIONAL CONFERENCE ON MULTIMEDIA AND EXPO, VOLS 1-4
Abstract
This paper addresses multimedia end user system design for content distribution over heterogeneous networks and terminals, with particular focus on End-to-End quality of service (QoS) control. A multimedia terminal comprising content-related metadata processor, usage environment characteristics provider, end user QoS monitor and H.264's extension Scalable Video Coding (SVC) audio-visual player in coordination under a terminal middleware, has been conceived and implemented. This end user terminal enables End-to-End QoS control for content adaptation solution both in semantic and physical approaches to maximize end user's perceptual experience and minimize resources. Such design approach illustrates a possible architecture for next generation multimedia end user terminal supporting MPEG-21 and H.264's extension SVC codec standards.
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