Rao-Blackwellised Particle Filter for Star-Convex Extended Target Tracking Models

In this paper, we explore the potential gains in using Sequential Monte Carlo (SMC) methods for extended target tracking (ETT) models based on Gaussian processes (GP). The existing random hypersurface based ETT models use Extended/Unscented Kalman filter for inference, which may lead to poor performance under high uncertainty. Particle filters (PFs) are known to provide robust performance in the cases where the non-linear Kalman filtering solutions fail. We design a Rao-Blackwellised particle filter (RBPF) where we exploit the conditional linear Gaussian structure of the GP parameters. We illustrate the gain in the performance with simulations

Cellulose from the green macroalgae Ulva lactuca: isolation, characterization, optotracing, and production of cellulose nanofibrils

We report (1) successful extraction and characterization of cellulose from northern hemisphere green macroalgae Ulva lactuca (Ulva fenestrata) collected along the Swedish west coast and cultivated indoors under controlled conditions, followed by (2) its utilization in the production of lignin-free cellulose nanofibrils (CNF). Cellulose was extracted by sequential treatment with ethanol, hydrogen peroxide, sodium hydroxide, and hydrochloric acid, yielding a cellulose-rich insoluble fraction. The extracted cellulose was disintegrated into CNF using a mechanical homogenization process without any further enzymatic pre-treatments. In addition, regenerated cellulose was prepared. XRD characterization of the CNF showed characteristic peaks for the cellulose I allomorph and confirmed that the nanofibrils were semicrystalline with a crystallinity index of 48%. Regenerated cellulose was mostly amorphous with an XRD pattern indicating the presence of the cellulose II allomorph. The cellulose fractions were essentially free from inorganic substances and thermally stable up to around 260 degrees C. Structural mapping with CP-MAS C-13-NMR sustains the cellulose content of CNF and regenerated cellulose, respectively, yet ion chromatography identified the presence of 10-15% xylose in the fractions. Optotracing was used as a novel and non-disruptive tool to selectively assess the polysaccharide composition of the cellulose fractions and produced CNF aiming to shed light on this hitherto non-resolved origin of xylose in Ulva cell wall matter. Fluorescence excitation and emission spectra of a panel of 4 oligothiophenes identified and verified the presence of cellulose and sustain the conclusion that the isolated fractions consist of cellulose intertwined with a small amount of a xylose-containing glucan copolymer. [GRAPHICS] .Funding Agencies|Royal Institute of Technology; Swedish Foundation for Strategic Research (SSF)Swedish Foundation for Strategic Research [RBP14-0045]; Erling-Persson Family Foundation; Getinge AB</p