Automatic reconstruction of 3D human arm motion from a monocular image sequence

A model-based approach to reconstruction of 3D human arm motion from a monocular image sequence taken under orthographic projection is presented. The reconstruction is divided into two stages. First, a 2D shape model is used to track the arm silhouettes and second-order curves are used to model the arm based on an iteratively reweighted least square method. As a result, 2D stick figures are extracted. In the second stage, the stick figures are backprojected into the scene. 3D postures are reconstructed using the constraints of a 3D kinematic model of the human arm. The motion of the arm is then derived as a transition between the arm postures. Applications of these results are foreseen in the analysis of human motion patterns. Received: 26 January 1996 / Accepted: 17 July 1997     

Tensile behavior of Basalt/Glass single and multilayer-woven fabrics

High strength fabrics are perfect materials for use in automotive and aerospace systems, where high performance and light weight structures are demanded. Mechanical characterization under constant loading is of great importance for these materials. The purpose of this study is to analyze the tensile properties of Basalt and Glass-woven structures at different pick density, weave design, stitch distance, and number of layers. For this purpose, single and double layerwoven fabric structures have been prepared using Basalt and Glass yarns on sample weaving loom. Their uniaxial testing has been performed to analyze their tensile curves. Analysis of variance showed the statistical significance of material, pick density, direction of applied load, weave, and stitching in strength of fabric, while the effect of stitch distance was insignificant.     

UV-/thermal processing of sol-gel-derived lead-magnesium-niobium titanate thin films

This work aimed to describe the sol-gel synthesis and preparation of a near-morphotropic phase boundary lead-magnesium-niobium titanate (PMNT) material system, and to investigate the influences of room-temperature-UV-irradiation and rapid thermal annealing (RTA) processes on the properties of its thin films. It was postulated that the use of UV-irradiation prior to thermal processing could play a role in the generation of a structural difference that would manifest itself via the formation of a higher film thickness, which was more pronounced at higher RTA temperatures The PMNT thin film system described here (particularly those annealed at higher temperatures) appeared to be potentially suitable for ultrahigh-value-capacitor applications; the unexposed film annealed at 750 °C exhibited the highest high k value (1425) with a strongly pronounced perovskite phase (97%).     

High sodium continuous veno‐venous hemodialysis with regional citrate anticoagulation and online dialysate generation in patients with acute liver failure and cerebral edema

Introduction: Acute liver failure is associated with a high mortality rate. Induction of plasma hypertonicity with mannitol or hypertonic saline remains the cornerstone in the management of resultant cerebral edema. Significant disadvantages of this approach include poor or unpredictable control of serum sodium concentration and volume expansion, among others. Methods: We used high sodium continuous veno‐venous hemodialysis with regional citrate anticoagulation and online dialysate generation to accurately control the serum sodium in eleven patients with acute liver failure, renal failure, and cerebral edema. We used a Fresenius 2008 K/K2 machine in hemodialysis mode to deliver a blood flow of 60 ml/minute and dialysate flow of 400 ml/minute. Our previously published protocol results in complete removal of infused citrate by the dialyzer. On‐line clearance calculations were used to model the time required to reach the target serum sodium. Findings: All patients achieved serum sodium within 2 mEq/L of target without fluctuations or rebound. Nine patients survived without requiring liver transplantation and two died despite reaching the prescribed serum sodium target. We did not encounter any citrate toxicity. Discussion: We describe a novel approach for delivering continuous osmotherapy to patients with acute liver failure, renal failure, and cerebral edema. In comparison to standard therapy, the described modality enables precise titration of serum sodium without undesirable fluctuations in extracellular fluid volume. A particular advantage is zero delivery of citrate to this vulnerable group of patients with acute liver failure.     

An electronic driver for improving the open and closed loop electro-mechanical response of Dielectric Elastomer actuators

Actuators based on Dielectric Elastomers are a promising technology in robotic and mechatronic applications. The overall actuator performances are influenced by the non-linear and highly coupled electrical and mechanical behavior of the employed materials. To date, the practical electro-mechanical response and controllability of actuators based on Dielectric Elastomers are limited by the inadequacy of the employed driving circuits, which are based on voltage-regulated converters. In this paper, first a novel activation strategy is proposed for Dielectric Elastomer actuators, which is based on a custom electronic driver derived from the flyback transformer topology. Second, two closed-loop controllers employing the proposed electronic driver are presented and compared for the accurate and fast regulation of the position of Dielectric Elastomer actuators. Experimental results are reported which show that the proposed electronic driver outperforms the traditional driving circuits in terms of energy efficiency, fast open-loop actuator activation and good closed-loop actuator controllability.     

On-line learning and modulation of periodic movements with nonlinear dynamical systems

The paper presents a two-layered system for (1) learning and encoding a periodic signal without any knowledge on its frequency and waveform, and (2) modulating the learned periodic trajectory in response to external events. The system is used to learn periodic tasks on a humanoid HOAP-2 robot. The first layer of the system is a dynamical system responsible for extracting the fundamental frequency of the input signal, based on adaptive frequency oscillators. The second layer is a dynamical system responsible for learning of the waveform based on a built-in learning algorithm. By combining the two dynamical systems into one system we can rapidly teach new trajectories to robots without any knowledge of the frequency of the demonstration signal. The system extracts and learns only one period of the demonstration signal. Furthermore, the trajectories are robust to perturbations and can be modulated to cope with a dynamic environment. The system is computationally inexpensive, works on-line for any periodic signal, requires no additional signal processing to determine the frequency of the input signal and can be applied in parallel to multiple dimensions. Additionally, it can adapt to changes in frequency and shape, e.g. to non-stationary signals, such as hand-generated signals and human demonstrations.

Assessment of naphthalene biodegradation efficiency of Pseudomonas and Burkholderia strains tested in soil model systems

The kinetic parameters of the naphthalene degradation process performed by indigenous and introduced microorganisms were studied in soil model systems. The introduction of active naphthalene‐degrading strains Pseudomonas putida BS3701 and G7 in soil model systems accelerated the naphthalene destruction process by a factor of three to four. Moreover, the addition of salicylate (0.1 mg g^?1 dry soil) to the systems containing the introduced microbial strains again doubled the rate of the naphthalene degradation process. To provide a quantitative assessment of the naphthalene biodegradation process, a mathematical model describing the bacterial growth, the consumption of the naphthalene, the production and subsequent consumption of naphthalene cleavage products, and the consumption of organic soil substances in soil model systems was developed. An approach for assessment of the degradation efficiency of low solubility polycyclic aromatic hydrocarbon provided by bacteria of genera Pseudomonas and Burkholderia in soil was suggested. The approach will enable comparison and selection of the most active degraders, which have the potential for application in biotechnologies for cleaning of soils contaminated by polycyclic aromatic hydrocarbons. Copyright © 2005 Society of Chemical Industry     

Electrocaloric properties of 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 ceramics with different grain sizes

We have investigated the electrocaloric (EC) properties of the ceramic 0.7Pb(Mg_1/3Nb_2/3)O₃–0.3PbTiO₃. A variety of samples with different median grain sizes, i.e., 1.0, 2.2 and 4.0?μm, and relative densities of about 96% were prepared using atmospheric sintering at 1200^oC for 2, 8 and 16?h. The ceramic material with a median grain size of 2.2?μm exhibited the highest value for the EC temperature change, i.e., 1.27?K at 60?kV?cm^?1, measured with a high-resolution calorimeter. This value is 25 and 19% higher than the value for the ceramics with the finer and the coarser grains, respectively.     

Bone‐specific alkaline phosphatase and bone turnover in African American hemodialysis patients

Introduction: Noninvasive measures of bone activity include intact parathyroid hormone (iPTH) and bone‐specific alkaline phosphatase (BSAP). Whether BSAP measurement alone or in combination with other biochemical data provides more reliable information about bone turnover than iPTH alone in African Americans on hemodialysis is unknown. Methods: This cross‐sectional study aimed to determine the optimal predictor and cutoff points for BSAP, iPTH, calcium and phosphorus in classifying bone biopsy findings. Forty‐three African American hemodialysis patients were available for analysis. Biochemical data on the day of biopsy across a spectrum of qualitative histologic bone features were compared. Classification and regression tree analysis was used to determine both the optimal predictor and cutoff points for BSAP, iPTH, calcium and phosphorus in identifying bone turnover status. Findings: Seven subjects had adynamic disease, 31 had mild/moderate hyperparathyroid bone features, and five had severe hyperparathyroid bone disease. BSAP was the optimal predictor of bone biopsy with a cutoff point of 22 ng/mL. Calcium and phosphorus had no predictive value. At BSAP ≤ 22 ng/mL, subjects had either adynamic bone disease or mild/moderate hyperparathyroid bone disease but iPTH was not useful in further classifying biopsy findings. When BSAP was >22 ng/mL, subjects had either mild/moderate or severe hyperparathyroid bone disease, and iPTH was useful in further classifying biopsy findings. With BSAP > 22 ng/mL and iPTH < 726 pg/mL, all subjects had mild/moderate bone turnover features. Discussion: Compared to iPTH, BSAP was shown to be the optimal predictor of biopsy findings with an optimal cutoff at 22 ng/mL.