Legal Statutes of Arab Refugees

The recently developed particle filter offers a general numerical tool to approximate the state a posteriori density in nonlinear and non-Gaussian filtering problems with arbitrary accuracy. Because the particle filter is fairly easy to implement and tune, it has quickly become a popular tool in signal processing applications. Its main drawback is that it is quite computer intensive. For a given filtering accuracy, the computational complexity increases quickly with the state dimension. One remedy to this problem is what in statistics is called Rao-Blackwellization, where states appearing linearly in the dynamics are marginalized out. This leads to that a Kalman filter is attached to each particle. Our main contribution here is to sort out when marginalization is possible for state space models, and to point out the implications in some typical signal processing applications. The methodology and impact in practice is illustrated on terrain navigation for aircrafts. The marginalized particle filter for a state-space model with nine states is evaluated on real aircraft data, and the result is that very good accuracy is achieved with quite reasonable complexity

Experimental and numerical determination of the hygroscopic warping of cross-laminated solid wood panels

The moisture-induced warping of three-layered cross-laminated solid wood panels made of Norway spruce was studied. The panels were exposed to different climate conditions at 65% and 100% relative humidity at the two panel faces. The results showed increasing cup deformation with an increasing relative thickness of the outer layers. The annual growth ring orientation was found to have a significant influence on the magnitude of the cup deformation. Measurements and numerical simulations of the moisture distribution within the panel were made in order to provide data for numerical simulations of the warping. A distinctive moisture profile with a conspicuous influence of the adhesive bond lines was found. The coefficient of diffusion of the adhesive bond lines was determined from the measurements and simulations. The mechanical material model used for the warping simulations takes into account elastic strain, moisture-induced swelling, and mechano-sorptive strain. The simulations showed good agreement with the warping test results. The most important material parameters for the cup deformation, which were identified in a parametric study of a panel with vertically oriented annual rings, are the moduli of elasticity and the swelling coefficients in the longitudinal and radial direction. Furthermore, the mechano-sorptive coefficient in radial direction was found to have a significant influence on war

Fracture mechanics studies of non-yielding materials like concrete : modelling of tensile fracture and applied strength analyses

Fracture mechanics studies of non-yielding materials are presented. The studies are based on theoretical models for the macroscopical mechanical behaviour of materials during tensile stress induced fracture. A number of applied numercal analysis are indicated. Fracture models and strength relations are discussed also from a few more general and fundamental points of view. A number of comparisons are made to test results from literature. The applications concern materials such as concrete, reinforced concrete, mortar and wood. Most numerical calculations are carried out by means of finite element methods. The fracture mechanics model called the fictìtious crack model is emphasized. This model gives a.description of gradual and localized fracture-softening in a single discrete tensile fracture process region. 0ther models dealt with: linear elastic fracture mechanics, Weibull-model, un-limited plasticity, conventional maximum stress theory and a few more special models. Specimens dealt with during numerical calculations: beams in bending, fracture mechanics tests specimens, tensile test specimens, pipes in bending and crushing, specimens with a re-entrant corner and longitudinally reinforced concrete beams in shear. According to the results obtained, it seems to be theoretically consistent and often of great practical importance to take into account the gradual and localized fracture-softening during strength analysis of specimens and structural elements

Finger-Joints and Laminated Wood. Final Report for the BFR-project

This report gives an overview and summary of research on wood-adhesive bonds performed during several years in a number of separate studies. These studies concern the mechanical testing, numerical analysis and constitutive modelling of wood-adhesive bonds in timber engineering. Applications such as finger-joints and glued-laminated timber are considered. The experimental studies include the testing of the fracture characteristics of wood-adhesive bonds. The numerical studies relate to the strength of finger-joints and laminated beams.In the experimental studies, the complete stress-displacement response of small specimens, particularly their fracture softening behaviour beyond peak stress, was recorded. A major outcome from the experiments is that wood-adhesive bonds can behave in a fracture-softening manner, and that it is possible to record this under stable conditions.In one of the numerical studies the finite element method was employed to analyse the stress distribution around zones of low stiffness in a laminated beam. A fracture mechanics analysis was also performed of the delamination of a laminated beam. The results show that the often made assumption of a stress redistribution taking place around weak zones is not necessarily true. Another finding is that the delamination of an initially cracked glulam beam tends to be increasingly dominated by mode II failure as the lamination thickness decreases.In another study, also related to finger-joints and laminated beams, the finger-joint failure in a glulam beam was simulated using a nonlinear fictitious crack model with stochastic properties. The results show the proposed approach to be able to account for such phenomena as the size effect and the laminating effect. Another observation is that finger-joint fracture energy, i.e. the ductility, has a major influence on lamination and beam strength. The influence of bondline defects on the tensile strength of a finger-joint was also investigated. It was demonstrated that even a small defect in the form of a glueline void, can have a relatively strong influence on the tensile strength. It was also demonstrated that the strength of finger-joints is largely inuenced by the outermost finger.Finally, an interface model based on damage mechanics is suggested for the modelling of wood-adhesive interfaces. This model accounts for joint dilatation and post-cracking friction. Also, a homogenisation scheme is presented for combining the proposed model with ordinary plasticity models for the adhesive bulk. This homogenisation procedure is based on assumptions regarding the stress and strain gradients typical of thin bondlines