Online Acoustic System Identification Exploiting Kalman Filtering and an Adaptive Impulse Response Subspace Model

We introduce a novel algorithm for online estimation of Acoustic Impulse Responses (AIRs) which allows for fast convergence by exploiting prior knowledge about the fundamental structure of AIRs. The proposed method assumes that the variability of AIRs of an acoustic scene is confined to a low-dimensional manifold which is embedded in a high-dimensional space of possible AIR estimates. We discuss various approaches which exploit a training data set of AIRs, e.g., high-accuracy AIR estimates from the acoustic scene, to learn a local affine subspace approximation of the AIR manifold. The model is motivated by the idea of describing the generally nonlinear AIR manifold locally by tangential hyperplanes and its validity is verified for simulated data. Subsequently, we describe how the manifold assumption can be used to enhance online AIR estimates by projecting them onto an adaptively estimated subspace. Motivated by the assumption of manifolds being locally Euclidean, the parameters determining the adaptive subspace are learned from the nearest neighbor AIR training samples to the current AIR estimate. To assess the proximity of training data AIRs to the current AIR estimate, we introduce a probabilistic extension of the Euclidean distance which improves the performance for applications with non-white excitation signals. Furthermore, we describe how model imperfections can be tackled by a soft projection of the AIR estimates. The proposed algorithm exhibits significantly faster convergence properties in comparison to a high-performance state-of-the-art algorithm. Furthermore, we show an improved steady-state performance for speech-excited system identification scenarios suffering from high-level interfering noise and nonunique solutions.

     

Whole Body Ip6k1 Deletion Protects Mice from Age-Induced Weight Gain,Insulin Resistance and Metabolic Dysfunction

(1) Background: We previously demonstrated that disruption of IP6K1 improves metabolism, protecting mice from high-fat diet-induced obesity, insulin resistance, and non-alcoholic fatty liver disease and steatohepatitis. Age-induced metabolic dysfunction is a major risk factor for metabolic diseases. The involvement of IP6K1 in this process is unknown. (2) Methods: Here, we compared body and fat mass, insulin sensitivity, energy expenditure and serum-, adipose tissue- and liver-metabolic parameters of chow-fed, aged, wild type (aWT) and whole body Ip6k1 knockout (aKO) mice. (3) Results: IP6K1 was upregulated in the adipose tissue and liver of aWT mice compared to young WT mice. Moreover, Ip6k1 deletion blocked age-induced increase in body- and fat-weight and insulin resistance in mice. aKO mice oxidized carbohydrates more efficiently. The knockouts displayed reduced levels of serum insulin, triglycerides, and non-esterified fatty acids. Ip6k1 deletion partly protected age-induced decline of the thermogenic uncoupling protein UCP1 in inguinal white adipose tissue. Targets inhibited by IP6K1 activity such as the insulin sensitivity- and energy expenditure-inducing protein kinases, protein kinase B (PKB/Akt) and AMP-activated protein kinase (AMPK), were activated in the adipose tissue and liver of aKO mice. (4) Conclusions: Ip6k1 deletion maintains healthy metabolism in aging and thus, targeting this kinase may delay the development of age-induced metabolic dysfunction.     

Influence of H2S addition during diamond deposition on hardmetal substrates

Diamond deposition on hardmetal substrates is an industrial process to increase the wear resistance of tools during machining operations, but till now an increase in diamond layer adhesion is desirable. The main problem during diamond deposition on hardmetal substrates is the Co content in the binder phase.H₂S was used for immobilizing the cobalt on the substrate surface. The H₂S should react with the metallic Co covering its surface with CoS. Because of this the diamond nucleation occurs easier and the Co vapour pressure is also reduced. Similar mechanisms were observed using silicon and boron vapour during substrate pre-treatment.Positive effects of H₂S addition were achieved if the H₂S is added only during the diamond nucleation period. The experiments with continuous H₂S addition were not successful.For comparison diamond deposition on Murakami/Carrot pre-treated substrates were carried out.     

Phytochemical composition and antioxidant capacity of various botanical parts of the fruits of Prunus × domestica L. from the Lorraine region of Europe

Mirabelle plums represent a famous fruit from the Lorraine region, however little is known about their phytochemical composition. The oil of the fruit contained predominantly oleic acid (59%) and linoleic acid (29%). The total content of phenolic antioxidants in the whole fruits was 5.338 g/kg with 456 mg/kg (9%), 701 mg/kg (13%) and 4159 mg/kg (78%) detected in the peels, flesh and pits respectively. The peels contained solely 3,4-dihydroxybenzoic acid (270 mg/kg) and rutin (186 mg/kg), the flesh exclusively echinoids (723 mg/kg), whereas the pits contained a rich variety of phenolic compounds (4.2 g/kg) dominated by amygdalin (3.8 g/kg), but with significant contributions from vanillin (102 mg/kg), guajacyl-glycerin-coniferyl aldehyde isomers (87 mg/kg), dehydro-diconiferyl aldehyde (52 mg/kg), and vanillin diglucoside (48 mg/kg). Of the major phenolic compounds tested across a range of in vitro assays, rutin was the superior antioxidant.     

Influences of WC-Co hard metal substrate pre-treatments with boron and silicon on low pressure diamond deposition

Diamond coatings were produced on WC-Co hard metal substrates. To improve the adhesion between the diamond coating and the substrate a substrate surface pre-treatment with boron or with silicon vapor was applied. This surface pre-treatment resulted in an increase in both the diamond nucleation density and the diamond growth rate. Simple adhesion tests confirmed an improved adhesion of thin diamond layers as compared with those on untreated hard metal substrates.Secondary ion mass spectroscopy (SIMS) depth profiles revealed an enrichment of B or of Si at the substrate-diamond interface due to the pre-treatment procedure. The correlation of the Co and W depth profiles in samples coated for 12 and 24 h supports the theory of diamond dissolution into the substrate. Co was detected only in the interface regions and on the surface of the diamond layers but not in the bulk of the thick layers. The SIMS results confirm X-ray examinations of the hard metal Co binder phase.     

A non-invasive technique for 3-dimensional assessment of articular cartilage thickness based on MRI. Part 2: Validation using CT arthrography

Established methods for the measurement of articular cartilage thickness are invasive and cannot be sequentially applied in living subjects. In the present study, the distribution of cartilage thickness throughout entire joint surfaces was determined from MR images obtained with a fat-suppressed gradient-echo sequence at a resolution of 0.31 x 0.31 x 2.00 mm3, and compared to that derived from CT arthrography. A minimal distance algorithm was employed to produce 3D cartilage thickness maps of seven cadaveric human knee joints. The mean amount of deviation of the cartilage volumes was 5.6% (+/- 4.6), statistical analysis showing that there was high agreement between the two methods (r = 0.995, slope = 1.037, y-intercept = -90.5 mm3). The 3D thickness maps yielded a striking agreement between the two methods, the maximum values generally yielding a deviation of none or one thickness interval of 0.5 mm. This investigation shows that accurate 3D assessment of articular cartilage thickness can be performed with MRI, this technique having the advantage that it is suitable for investigating living subjects.     

Diamond deposition on hardmetal substrates – Comparison of substrate pre-treatments and industrial applications

Diamond deposition on various hardmetal tools is widely used. For applications where the mechanical forces are low diamond coatings have long lifetimes, but especially for heavy duty applications the reproducibility of the diamond coating adhesion is not adequate.     

Detecting interaction above digital tabletops using a single depth camera

Digital tabletop environments offer a huge potential to realize application scenarios where multiple users interact simultaneously or aim to solve collaborative tasks. So far, research in this field focuses on touch and tangible interaction, which only takes place on the tabletop’s surface. First approaches aim at involving the space above the surface, e.g., by employing freehand gestures. However, these are either limited to specific scenarios or employ obtrusive tracking solutions. In this paper, we propose an approach to unobtrusively segment and detect interaction above a digital surface using a depth sensing camera. To achieve this, we adapt a previously presented approach that segments arms in depth data from a front-view to a top-view setup facilitating the detection of hand positions. Moreover, we propose a novel algorithm to merge segments and give a comparison to the original segmentation algorithm. Since the algorithm involves a large number of parameters, estimating the optimal configuration is necessary. To accomplish this, we describe a low effort approach to estimate the parameter configuration based on simulated annealing. An evaluation of our system to detect hands shows that a repositioning precision of approximately 1 cm is achieved. This accuracy is sufficient to reliably realize interaction metaphors above a surface.