Democratic heroism - Directive 2006/24/EC and the struggle for the soul of democracy

In the debate on how to make democracy strong against terrorism, it has been suggested that the Western democracies need new protective measures. This paper argues that, far from protecting democracy, such measures may in fact undermine the very values and virtues that make democracy possible. Information freedom, the right to due process and the protection of privacy are all fundamental for the functioning of a democratic society. Despite this, recent years have seen a string of new laws, both in the US and in Europe, that in different ways curtail key civil liberties. Even countries entirely unaffected by international terrorism, such as Sweden, have passed new legislation allowing electronic surveillance and covert listening devices. Taking the recent Swedish legislation as its starting point, the paper will also address the related EC directive on data retention (2006/24/EC). A key question posed is to what extent democracy has to be based on courage or even “heroism” if it is to remain true to itself when confronted by terrorism or other existential threats

The direct and inverse problem for obliquely incident transient elastodynamic waves

The direct and inverse scattering problems for a plane-stratified viscoelastic medium excited by a transient plane wave of SH or P-SV type are treated. The viscoelastic medium is characterized by two time and space dependent memory functions and a spatially dependent density. The direct and inverse problems are solved by a time-domain wave propagator method that is related to the Green functions technique and the imbedding method. The definition of the wave-propagators is based upon a wave-splitting technique where the total wave is split into generalized left and right going components. A numerical algorithm for the inverse problem is presented for the P-SV case

Design of reflextionless slabs for transient electromagnetic waves

A method for modeling reflectionless conductive dispersive slabs is presented. The slabs are impedance matched to the surrounding half-spaces and are temporally dispersive with a spatially varying impedance. It is shown that the effects from the variation of the impedance can be matched by the temporal dispersive effects and the conductivity so that for a normally incident plane wave the slab does not reflect any field regardless of the shape of the incident transient field. The problem of finding reflectionless media is formulated as an inverse problem where the constitutive relation is to be determined as a function of depth given a reflection kernel which is zero. The inverse problem is solved by a time domain Green functions technique

Non-reflecting dispersive media

The modeling of non-reflecting one-dimensional dispersive media is discussed. The media are temporal dispersive with a spatially varying impedance. It is shown that the effects from the variation of the impedance can be matched by the temporal dispersive effects so that the media do not reflect any field regardless of the shape of the incident transient field. The problem of finding reflectionless media is formulated as an inverse problem where the constitutive relation is to be determined as a function of depth given a reflection kernel which is zero. Atime domain Green functions technique is used to solve the inverse problem

Accelerating jackknife resampling for the Canonical Polyadic Decomposition

The Canonical Polyadic (CP) tensor decomposition is frequently used as a model in applications in a variety of different fields. Using jackknife resampling to estimate parameter uncertainties is often desirable but results in an increase of the already high computational cost. Upon observation that the resampled tensors, though different, are nearly identical, we show that it is possible to extend the recently proposed Concurrent ALS (CALS) technique to a jackknife resampling scenario. This extension gives access to the computational efficiency advantage of CALS for the price of a modest increase (typically a few percent) in the number of floating point operations. Numerical experiments on both synthetic and real-world datasets demonstrate that the new workflow based on a CALS extension can be several times faster than a straightforward workflow where the jackknife submodels are processed individually

Performance requirements for Swedish transport infrastructure - A pre-study of challenges and possibilities

In recent years, significant worldwide research has been conducted regarding the performance assessment of bridges and the concept of performance indicator has been introduced However, there are still significant discrepancies in how these indicators are obtained and used. Simultaneously, it is desirable to achieve processes and methods that are direct, i.e. that measured values are directly compared with projected values over time. This project concerns methods for verification of technical performance requirements. The feasibility study brought together interdisciplinary researchers, consultants, and entrepreneurs to gather knowledge, anchor the research agenda, and implement performance requirements. The project concludes that there is a need for a “Holistic multi-parameter verification/validation system” that relies on the knowledge gained in structural health monitoring research

Coherent combining of low-power optical signals based on optically amplified error feedback

In free-space optical communication links, the combining of optical signals from multiple apertures is a well-known method to collect more power for improved sensitivity or mitigation of atmospheric disturbances. However, for analog optical combining no detailed analysis has been made in cases when the optical signal power is very low (<-60 dBm) as would be the case in very long-haul free-space links. We present a theoretical and experimental study of analog coherent combining of noise-limited signals from multiple independent apertures by applying low frequency optical phase dithering to actively compensate the relative phases. It is experimentally demonstrated that a 97% combining efficiency of four 10 GBaud QPSK signals is possible with a signal power per aperture exceeding -80 dBm, in fair agreement with theory. We also discuss the scaling aspects to many apertures

Process for verification of performance requirements for transport infrastructure

In recent years, significant worldwide research has been conducted regarding the performance assessment of bridges and the concept of performance indicator has been introduced However, there are still significant discrepancies in how these indicators are obtained and used. Simultaneously, it is desirable to achieve processes and methods that are direct, i.e. that measured values are directly compared with projected values over time. This project concerns methods for verification of technical performance requirements. The feasibility study brought together interdisciplinary researchers, consultants, and entrepreneurs to gather knowledge, anchor the research agenda, and implement performance requirements. The project concludes that there is a need for a “Holistic multi-parameter verification/validation system” that relies on the knowledge gained in structural health monitoring research

Life Cycle Sustainability Performance Assessment Method for Comparison of Civil Engineering Works Design Concepts: Case Study of a Bridge

Standardized and transparent life cycle sustainability performance assessment methods are essential for improving the sustainability of civil engineering works. The purpose of this paper is to demonstrate the potential of using a life cycle sustainability assessment method in a road bridge case study. The method is in line with requirements of relevant standards, uses life cycle assessment, life cycle costs and incomes, and environmental externalities, and applies normalization and weighting of indicators. The case study involves a short-span bridge in a design-build infrastructure project, which was selected for its generality. Two bridge design concepts are assessed and compared: a concrete slab frame bridge and a soil-steel composite bridge. Data available in the contractor’s tender phase are used. The two primary aims of this study are (1) to analyse the practical application potential of the method in carrying out transparent sustainability assessments of design concepts in the early planning and design stages, and (2) to examine the results obtained in the case study to identify indicators in different life cycle stages and elements of the civil engineering works project with the largest impacts on sustainability. The results show that the method facilitates comparisons of the life cycle sustainability performance of design concepts at the indicator and construction element levels, enabling better-informed and more impartial design decisions to be made