The design of curved optical waveguides : analytical and numerical analysis

A model for understanding the formation and propagation of modes in curved optical waveguides is developed. A numerical method for the calculation of curved waveguide mode profiles and propagation constants in two dimensional waveguides is developed, implemented and tested. A numerical method for the analysis of propagation of modes in three dimensional curved optical waveguides is developed, implemented and tested. A technique for the design of curved waveguides with reduced transition loss is presented. A scheme for drawing these new waveguides and ensuring that they have constant width is also provided. Claims about the waveguide design technique are substantiated through numerical simulations.

Extended nonlinear analytical models of compliant parallelogram mechanisms: third-order models

This paper proposes extended nonlinear analytical models, third-order models, of compliant parallelogram mechanisms. These models are capable of capturing the accurate effects from the very large axial force within the transverse motion range of 10% of the beam length through incorporating the terms associated with the high-order (up to third-order) axial force. Firstly, the free-body diagram method is employed to derive the nonlinear analytical model for a basic compliant parallelogram mechanism based on load-displacement relations of a single beam, geometry compatibility conditions, and load-equilibrium conditions. The procedures for the forward solutions and inverse solutions are described. Nonlinear analytical models for guided compliant multi-beam parallelogram mechanisms are then obtained. A case study of the compound compliant parallelogram mechanism, composed of two basic compliant parallelogram mechanisms in symmetry, is further implemented. This work intends to estimate the internal axial force change, the transverse force change, and the transverse stiffness change with the transverse motion using the proposed third-order model in comparison with the first-order model proposed in the prior art. In addition, FEA (finite element analysis) results validate the accuracy of the third-order model for a typical example. It is shown that in the case study the slenderness ratio affects the result discrepancy between the third-order model and the first-order model significantly, and the third-order model can illustrate a non-monotonic transverse stiffness curve if the beam is thin enough.

The analytical approach of the European Court of Human Rights in surveillance cases—the implications, justifications, and future of the Court’s reasoning, with a focus on the legislative impact in Ireland

A notable feature of the surveillance case law of the European Court of Human Rights has been the tendency of the Court to focus on the “in accordance with the law” aspect of the Article 8 ECHR inquiry. This focus has been the subject of some criticism, but the impact of this approach on the manner in which domestic surveillance legislation has been formulated in the Party States has received little scholarly attention. This thesis addresses that gap in the literature through its consideration of the Interception of Postal Packets and Telecommunications Messages (Regulation) Act, 1993 and the Criminal Justice (Surveillance) Act, 2009. While both Acts provide several of the safeguards endorsed by the European Court of Human Rights, this thesis finds that they suffer from a number of crucial weaknesses that undermine the protection of privacy. This thesis demonstrates how the focus of the European Court of Human Rights on the “in accordance with the law” test has resulted in some positive legislative change. Notwithstanding this fact, it is maintained that the legality approach has gained prominence at the expense of a full consideration of the “necessary in a democratic society” inquiry. This has resulted in superficial legislative responses at the domestic level, including from the Irish government. Notably, through the examination of a number of more recent cases, this project discerns a significant alteration in the interpretive approach adopted by the European Court of Human Rights regarding the application of the necessity test. The implications of this development are considered and the outlook for Irish surveillance legislation is assessed.