Família multigeracional e relações intergeracionais : perspectiva sistémica

Os sistemas familiares multigeracionais (três ou mais gerações vivas) passaram de raros no passado a uma realidade social cada vez mais comum na actualidade, devido ao fenómeno demográfico de envelhecimento populacional. Este estudo pretende contribuir para o conhecimento deste sistema social, situado entre a família nuclear e a comunidade, procurando descrever a sua estrutura, funções e padrões relacionais dos seus membros com outros familiares e com os sistemas sociais envolventes. Para tal, foi organizada uma amostra de 25 famílias multigeracionais (contendo quatro gerações), à qual foi aplicada uma entrevista de genograma a um elemento das gerações intermédias e quatro entrevistas de análise da rede social pessoal (uma por geração), perfazendo um total de 25 entrevistas de genograma e 92 de avaliação da rede social (menos 8 do que o esperado devido a mortalidade experimental). A análise dos dados possibilitou: 1) a aplicação do princípio de totalidade sistémica à família multigeracional, a sua definição como um sistema social de complexidade idiossincrática, a identificação dos subsistemas que compõem o objecto de estudo (indivíduo, núcleo familiar, composição familiar, geração, linhagem), e a definição de uma tipologia familiar multigeracional (família unificada, dispersa e fragmentada); 2) a identificação e análise de papéis sociais desempenhados pelos indivíduos no contexto familiar multigeracional especificamente relevantes neste nível sistémico (guardião das memórias familiares, elo de ligação familiar, pronto-socorro familiar); 3) a descrição das redes sociais pessoais e a identificação das diferenças estruturais e funcionais entre indivíduos pertencentes a diferentes subsistemas geracionais, que permitem reflectir sobre a evolução da rede social ao longo das várias fases de desenvolvimento individual e familiar; 4) um conhecimento mais aprofundado das redes sociais dos indivíduos mais idosos que pertencem a famílias multigeracionais, da composição da matriz relacional percepcionada como significativa e apoios disponibilizados. Em suma, os dois primeiros capítulos reflectem o esforço de desenvolvimento de um modelo heurístico para o sistema familiar multigeracional, numa perspectiva estruturalista, enquanto os dois capítulos subsequentes, apoiandose conceptualmente nos anteriores, facultam um quadro das relações entre subsistemas geracionais na actualidade, através de uma metodologia de análise das redes sociais. ABSTRACT: Multigenerational family systems comprising four generations are increasingly common nowadays due to the demographic phenomenon of population aging. This study aims at a deeper understanding of this social system, placed between the nuclear family and the community, in particular by describing its structure, functions and relational patterns of its members with other members in the family and surrounding social systems. A sample of 25 multigenerational families (comprising four generations) was selected. A genogram interview was applied to a member of the middle generations, and four personal social network questionnaires were administered to one element of each generation. A total of 25 genograms and 92 social network inventories were collected (minus 8 than expected due to experimental mortality). Main findings were: 1) the application of systemic principles to the multigenerational family, which allowed us to define it as a social system of idiosyncratic complexity, involving specific subsystems (individual, family nucleus, family composition, generation, lineage), and also to define a multigenerational family typology (unified, dispersed and fragmented family); 2) the identification and analysis of social roles assumed by individuals in the multigenerational family context, that are specifically relevant in this systemic level (keeper of family memories, connecting link in the family, family first aider); 3) the description of the personal social networks and the identification of structural and functional differences among individuals belonging to different generational subsystems, which allowed for a reflection on the evolution of social networks through the various stages of individual and family development; 4) a deeper knowledge of the eldest family members social networks, i.e. the relational matrix of significant individuals and supports in oldold age. In summary, the first two chapters reflect the development of a heuristic model directed at the multigenerational family, whereas the two subsequent chapters provide a view of contemporaneous relationships between generational subsystems, through a social network analysis methodology.

Characterization of RSOA modulators in radio over fiber links

In this work physical and behavioral models for a bulk Reflective Semiconductor Optical Amplifier (RSOA) modulator in Radio over Fiber (RoF) links are proposed. The transmission performance of the RSOA modulator is predicted under broadband signal drive. At first, the simplified physical model for the RSOA modulator in RoF links is proposed, which is based on the rate equation and traveling-wave equations with several assumptions. The model is implemented with the Symbolically Defined Devices (SDD) in Advanced Design System (ADS) and validated with experimental results. Detailed analysis regarding optical gain, harmonic and intermodulation distortions, and transmission performance is performed. The distribution of the carrier and Amplified Spontaneous Emission (ASE) is also demonstrated. Behavioral modeling of the RSOA modulator is to enable us to investigate the nonlinear distortion of the RSOA modulator from another perspective in system level. The Amplitude-to-Amplitude Conversion (AM-AM) and Amplitude-to-Phase Conversion (AM-PM) distortions of the RSOA modulator are demonstrated based on an Artificial Neural Network (ANN) and a generalized polynomial model. Another behavioral model based on Xparameters was obtained from the physical model. Compensation of the nonlinearity of the RSOA modulator is carried out based on a memory polynomial model. The nonlinear distortion of the RSOA modulator is reduced successfully. The improvement of the 3rd order intermodulation distortion is up to 17 dB. The Error Vector Magnitude (EVM) is improved from 6.1% to 2.0%. In the last part of this work, the performance of Fibre Optic Networks for Distributed and Extendible Heterogeneous Radio Architectures and Service Provisioning (FUTON) systems, which is the four-channel virtual Multiple Input Multiple Output (MIMO), is predicted by using the developed physical model. Based on Subcarrier Multiplexing (SCM) techniques, four-channel signals with 100 MHz bandwidth per channel are generated and used to drive the RSOA modulator. The transmission performance of the RSOA modulator under the broadband multi channels is depicted with the figure of merit, EVM under di erent adrature Amplitude Modulation (QAM) level of 64 and 254 for various number of Orthogonal Frequency Division Multiplexing (OFDM) subcarriers of 64, 512, 1024 and 2048.