Um estudo de performance de uma ferramenta de Object/Relational Mapping

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Amorphous silicon e 3D sensors applied to object detection

Nowadays, existing 3D scanning cameras and microscopes in the market use digital or discrete sensors, such as CCDs or CMOS for object detection applications. However, these combined systems are not fast enough for some application scenarios since they require large data processing resources and can be cumbersome. Thereby, there is a clear interest in exploring the possibilities and performances of analogue sensors such as arrays of position sensitive detectors with the final goal of integrating them in 3D scanning cameras or microscopes for object detection purposes. The work performed in this thesis deals with the implementation of prototype systems in order to explore the application of object detection using amorphous silicon position sensors of 32 and 128 lines which were produced in the clean room at CENIMAT-CEMOP. During the first phase of this work, the fabrication and the study of the static and dynamic specifications of the sensors as well as their conditioning in relation to the existing scientific and technological knowledge became a starting point. Subsequently, relevant data acquisition and suitable signal processing electronics were assembled. Various prototypes were developed for the 32 and 128 array PSD sensors. Appropriate optical solutions were integrated to work together with the constructed prototypes, allowing the required experiments to be carried out and allowing the achievement of the results presented in this thesis. All control, data acquisition and 3D rendering platform software was implemented for the existing systems. All these components were combined together to form several integrated systems for the 32 and 128 line PSD 3D sensors. The performance of the 32 PSD array sensor and system was evaluated for machine vision applications such as for example 3D object rendering as well as for microscopy applications such as for example micro object movement detection. Trials were also performed involving the 128 array PSD sensor systems. Sensor channel non-linearities of approximately 4 to 7% were obtained. Overall results obtained show the possibility of using a linear array of 32/128 1D line sensors based on the amorphous silicon technology to render 3D profiles of objects. The system and setup presented allows 3D rendering at high speeds and at high frame rates. The minimum detail or gap that can be detected by the sensor system is approximately 350 μm when using this current setup. It is also possible to render an object in 3D within a scanning angle range of 15º to 85º and identify its real height as a function of the scanning angle and the image displacement distance on the sensor. Simple and not so simple objects, such as a rubber and a plastic fork, can be rendered in 3D properly and accurately also at high resolution, using this sensor and system platform. The nip structure sensor system can detect primary and even derived colors of objects by a proper adjustment of the integration time of the system and by combining white, red, green and blue (RGB) light sources. A mean colorimetric error of 25.7 was obtained. It is also possible to detect the movement of micrometer objects using the 32 PSD sensor system. This kind of setup offers the possibility to detect if a micro object is moving, what are its dimensions and what is its position in two dimensions, even at high speeds. Results show a non-linearity of about 3% and a spatial resolution of < 2µm.

Human activity recognition with accelerometry: novel time and frequency features

Human Activity Recognition systems require objective and reliable methods that can be used in the daily routine and must offer consistent results according with the performed activities. These systems are under development and offer objective and personalized support for several applications such as the healthcare area. This thesis aims to create a framework for human activities recognition based on accelerometry signals. Some new features and techniques inspired in the audio recognition methodology are introduced in this work, namely Log Scale Power Bandwidth and the Markov Models application. The Forward Feature Selection was adopted as the feature selection algorithm in order to improve the clustering performances and limit the computational demands. This method selects the most suitable set of features for activities recognition in accelerometry from a 423th dimensional feature vector. Several Machine Learning algorithms were applied to the used accelerometry databases – FCHA and PAMAP databases - and these showed promising results in activities recognition. The developed algorithm set constitutes a mighty contribution for the development of reliable evaluation methods of movement disorders for diagnosis and treatment applications.

‘Wooden Man’? : Masculinities in the Work of J. M. Coetzee (Boyhood, Youth and Summertime)

In seeking to advance the possibility of justice, gender and postcolonial studies have argued for the importance of the study of masculinities, through the acknowledgment that a richer understanding of such gendered formations may provide the basis for recognition of the Other and that, left uncriticised, such formations may be continuously delineated by the reproduction of systems of domination. The current study finds as its object the representations of masculinities in J. M. Coetzee’s Boyhood (1997), Youth (2002) and Summertime (2009). As works of transition in terms of Coetzee’s oeuvre - post-apartheid and post-Disgrace - the trilogy provides an account of the development of a man through several stages of life. While portraying the tensions of different geographical and cultural locations, such as apartheid South Africa and the London of the Sixties, the trilogy articulates the various norms that impact in the formation of gender, particularly of masculinities, through a complex system of power relations. The adherence to such norms is never linear, as the trilogy provides imaginative accounts of the contradictions that assist in the formulation of gender, depicting both the allure and the terror that constitute hegemonic masculinity. Located in the intersection of gender and postcolonial studies, the present study is based on the works by Raewyn Connell on masculinities. Animated by such a critical framework, the main research question of the present study is whether the trilogy advances a notion of masculinity that differs from the traditional rigid model, that is, whether there is resistance to hegemonic masculinity and what the spaces inhabited by the subaltern are. It is suggested that the trilogy presents the reader with instances of resistance to normative formulations of masculinity, by contrasting domination with the possibility of justice, and advancing an understanding of the often fatal consequences of gender norms to one’s sense of being in the world.