Accuracy evaluation of two markerless motion capture systems for measurement of upper extremities: Kinect V2 and Captiv

Motion capturing is a promising method to assess working postures and human movements and, therewith, the risk of musculoskeletal injuries that could occur while performing manual tasks in industrial settings. To obtain a reliable risk assessment, the motion capture system used has to accurately measure body postures adopted by the worker during the task. This study evaluates the accuracy to measure joint angles of upper extremities of two different motion capture systems, namely the Microsoft Kinect V2 and the Captiv system, for angles of upper extremities. For this purpose, an experimental study was conducted involving 12 subjects performing preset static postures and basic movements, including elbow flexion, shoulder flexion, and shoulder abduction. In addition, to examine whether self‐occlusion or occlusion of body parts by work equipment has an impact on the accuracy of the Kinect V2, the subjects handled boxes during some of the tests. As a gold standard, a goniometer for static and an angle scale for dynamic exercises was used. The Captiv system shows high correlation coefficients (r > .93) and small mean absolute errors (<5°) for all movements except for elbow flexion. The Kinect V2 has sufficient results for joint angles captured without occlusion as well, but the accuracy significantly decreases when occlusion occurs.     

Preserved word-stem-completion priming of semantically encoded information in Alzheimer's disease.

Alzheimer's disease (AD) patients and normal elderly control subjects completed 80 standardized sentence frames with single words, yielding a measure of semantic memory. Memory for best fit sentence endings was then tested either explicitly, with a forced-choice recognition task, or implicitly, with a word-stem-completion task. The patients completed fewer sentences with best fit word endings than did the control subjects. Explicit retention was markedly defective in the AD group, but word-stem completion was normal. The preserved word-stem completion in AD is discussed in terms of encoding operations and transfer-appropriate processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anisotropic interface induced formation of Sb nanowires on GaSb(111)A substrates

The growth of Sb nanowires on GaSb(111)A substrates is studied by in?situ azimuthal scan reflection high-energy electron diffraction (ARHEED). Bulk and layer contributions can be distinguished in the ARHEED transmission pattern through the Sb nanowires. The three-dimensional structure of the growing Sb nanowires is identified by post-growth atomic force microscopy (AFM) and x-ray diffraction (XRD). The lattice match of the Sb crystal along the [Formula: see text] and the GaSb crystal along [Formula: see text] directions lead to a preferential orientation of the Sb nanowires. The Sb adsorption and desorption kinetics is studied by thermal desorption spectroscopy.     

Cryptococcosis in HIV infection of man: an epidemiological and immunological indicator?

Cryptococcosis is an epidemiological and immunological indicator due to the absence of Cryptococcus neoformans as a saprophyte in immunocompetent humans and the advantage of specific C. neoformans culture. On this basis, a report is presented on the CD4 lymphocyte count of 36 AIDS patients suffering from cryptococcosis and other concomitant or missing opportunistic AIDS-defining infections. In 26 out of 36 patients, i.e. 72%, a CD4 lymphocyte count of < or = 50/microL (mean value 39.5%) was found. Cryptococcosis as the sole opportunistic infection was diagnosed in 5 cases (13.9%). In 31 cases, various combinations of AIDS-associated diseases were found: Pneumocystis carinii pneumonia (PCP) (n = 19), cytomegalovirus infection (CMV) (n = 10), Kaposi's sarcoma (n = 6), Mycobacterium avium intracellulare infection (MAI) (n = 5), pneumonia (n = 2), toxoplasmosis (n = 2), Candida esophagitis (n = 1), tuberculosis (n = 1), lambliasis (n = 1), salmonellosis (n = 1) and wasting syndrome (n = 5). The conspicuous simultaneous occurrence or succession of pneumocystosis and cryptococcosis and the contrasting absence of aspergillosis and mucormycosis (zygomycosis) are commented. Based on the present observations in HIV-infected persons in Berlin, a CD4 lymphocyte count of < 150/microL may be used as a parameter indicating a predisposition for cryptococcosis as an airborne AIDS-defining infection. Attention is drawn to bird droppings as the sole habitat of C. neoformans and accidental niche of various other microorganisms.     

Finite Element Analysis using Component Decomposition and Knowledge-Based Control

This paper presents ongoing research into using Artificial Intelligence (AI) techniques to intelligently control finite element thermal analyses. These techniques are used to implement component level decomposition of the physical domain, and to integrate domain information into the analysis process to increase computational efficiency. We have implemented these techniques into a new proof-of-concept finite element program which employs a blackboard architecture to integrate the various numerical and symbolic knowledge sources. The blackboard architecture also supports the storage (and retrieval) of data in an object-oriented form. A test problem involving transient thermal analysis of an integrated circuit package is presented. Use of the proposed method showed a significant decrease in the number of floating point operations required compared to conventional solution technologies. The penalty associated with this saving was approximately a 4% difference in the calculated temperature in the critical region of interest.     

THz Induced Nonlinear Effects in Materials at Intensities above 26 GW/cm<Superscript>2</Superscript>

Nonlinear refractive index and absorption coefficient are measured for common semiconductor material such as silicon and organic molecule such as lactose in the terahertz (THz) spectral regime extending from 0.1 to 3 THz. Terahertz pulses with field strengths in excess of 4.4 MV/cm have been employed. Transmittance and the transmitted spectrum were measured with Z-scan and single shot noncollinear electro-optic pump-probe techniques. The THz-induced change in the refractive index (Δn) shows frequency-dependence and a maximum change of \(-~0.128\) at 1.37 THz in lactose and up to \(+~0.169\) at 0.15 THz in silicon was measured for a peak incident THz intensity of 26 GW/cm². Furthermore, the refractive index variation shows a quadratic dependence on the incident THz field, implying the dominance of third-order nonlinearity.     

Growth and characterization of undoped and N-type (Te) doped MOVPE grown gallium antimonide

The growth of GaSb by MOVPE and itsn-type doping using a dimethyltellurium dopant source are investigated. The results of growth rate, morphology and Te incorporation as a function of growth parameters are given. Increasing growth temperature and V/III reactant ratio were found to reduce the Te incorporation. The lowest Hall carrier concentrations obtained at room-temperature, onp-type andn-type MOVPE GaSb are respectively:p _H= 2.2 × 10¹⁶cm⁻³ with a Hall mobility ofμ _H= 860 cm²/V.s andn _H= 8.5 × 10¹⁵cm⁻³ withμ _H= 3860 cm²/V.s. Furthermore, Hall mobilities as high as 5000 cm²/V.s were measured onn-type GaSb samples.