Innovative drive concept for machining robots

In this paper an innovative drive concept for robots to improve their machining capability is presented. As a test bed a two-axis robot is designed and equipped with torque motors with load-sided high resolution encoders in addition to conventional gear motors with harmonic drive gearboxes. The gear motors are used for positioning tasks while the torque motors in particular compensate static and dynamic load-sided angle errors. The model-based control algorithm is decoupled and separately actuates both the servo gear and torque motors. It is shown that a considerable increase of performance is possible when adding the torque motors especially regarding the compensation of dynamic angle errors. The paper will present the design and details of the new drive concept, the modeling basics and first simulation results

Исследование и разработка гистерезисных электрических машин на основе деформируемого сплава Fe-Cr-Co

В ходе научно-квалификационной работы исследован материал ротора синхронного гистерезисного двигателя (СГД) из сплава 22Х15КА ГОСТ 24897-81. Получены динамические магнитные характеристики сплава на частотах перемагничивания от 50 Гц до 2 кГц. Представлены результаты исследования СГД в программной среде AnsysMaxwell 2D/3D.In the course of the scientific and qualifying work, the rotor material of the synchronous hysteresis motor from alloy 22Х15КА GOST 24897-81 was investigated. Dynamic magnetic characteristics of the alloy at the magnetization reversal frequencies from 50 Hz to 2 kHz are obtained. The results of the study of a synchronous hysteresis motor in the software environment of AnsysMaxwell 2D / 3D are presented

Vocational perspectives after spinal cord injury

Objective: To give insight into the vocational situation several years after a traumatic spinal cord injury (SCI) and describe the personal experiences and unmet needs; to give an overview of health and functional status per type of SCI and their relationship with employment status. Design: Descriptive analysis of data from a questionnaire. Setting: Dutch rehabilitation centre with special department for patients with spinal cord injuries. Subjects: Fifty-seven patients with a traumatic SCI, aged 18-60 years, admitted to the rehabilitation centre from 1990 to 1998. Main measures: Questionnaire with items related to vocational outcome, job experiences, health and functional status. Results: Of 49 patients who were working at the moment of SCI 60% currently had a paid job. Vocational outcome was related to a higher educational level. A significant relation between the SCI-specific health and functional status and employment was not found. The respondents who changed to a new employer needed more time to resume work, but seemed more satisfied with the job and lost fewer working hours than those who resumed work with the same employer. In spite of reasonable to good satisfaction with the current work situation, several negative experiences and unmet needs were reported. Conclusions: Despite a high participation in paid work following SCI, the effort of the disabled worker to have and keep a job should not be underestimated

Formation of phase lags at the cyclotron energies in the pulse profiles of magnetized, accreting neutron stars

Context: Accretion-powered X-ray pulsars show highly energy-dependent and complex pulse-profile morphologies. Significant deviations from the average pulse profile can appear, in particular close to the cyclotron line energies. These deviations can be described as energy-dependent phase lags, that is, as energy-dependent shifts of main features in the pulse profile. Aims: Using a numerical study we explore the effect of cyclotron resonant scattering on observable, energy-resolved pulse profiles. Methods: We generated the observable emission as a function of spin phase, using Monte Carlo simulations for cyclotron resonant scattering and a numerical ray-tracing routine accounting for general relativistic light-bending effects on the intrinsic emission from the accretion columns. Results: We find strong changes in the pulse profile coincident with the cyclotron line energies. Features in the pulse profile vary strongly with respect to the average pulse profile with the observing geometry and shift and smear out in energy additionally when assuming a non-static plasma. Conclusions: We demonstrate how phase lags at the cyclotron energies arise as a consequence of the effects of angular redistribution of X-rays by cyclotron resonance scattering in a strong magnetic field combined with relativistic effects. We also show that phase lags are strongly dependent on the accretion geometry. These intrinsic effects will in principle allow us to constrain a system's accretion geometry.Comment: 4 pages, 4 figures; updated reference lis

Toxicity Analysis in the ADEBAR Trial: Sequential Anthracycline-Taxane Therapy Compared with FEC120 for the Adjuvant Treatment of High-Risk Breast Cancer

Background: Data from meta-analyses have shown taxane-containing therapies to be superior to anthracycline-based treatments for high-risk breast cancer. Patients and Methods: The ADEBAR trial was a multicenter phase Ill trial in which patients with lymph node-positive breast cancer were prospectively randomized for either sequential anthracycline-taxane or FEC120 therapy. Patients received 4x epirubicin (90 mg/m(2)) and cyclophosphamide (600 mg/m(2)) every 3 weeks (q3w), followed by 4x docetaxel (100 mg/m(2)) q3w (EC-Doc arm), or 6x epirubicin (60 mg/m(2)) and 5-fluorouracil (500 mg/m(2)) on days 1 and 8 and cyclophosphamide (75 mg/m(2)) on days 1-14, q4w (FEC arm). We compared both arms with respect to toxicity and feasibility. Results: Hematological toxicity was found significantly more often in the FEC arm. Febrile neutropenia was seen in 11.3% of patients in the FEC arm and in 8.4% of patients in the EC-Doc arm (p = 0.027). Non-hematological side effects of grade 3/4 were rarely seen in either arm. Therapy was terminated due to toxicity in 3.7% of the patients in the EC-Doc arm and in 8.0% of the patients in the FEC arm (p = 0.0009). Conclusion: The sequential anthracycline-taxane regimen is a well-tolerated and feasible alternative to FEC120 therapy

Cyclotron resonant scattering feature simulations. I. Thermally averaged cyclotron scattering cross sections, mean free photon-path tables, and electron momentum sampling

Electron cyclotron resonant scattering features (CRSFs) are observed as absorption-like lines in the spectra of X-ray pulsars. A significant fraction of the computing time for Monte Carlo simulations of these quantum mechanical features is spent on the calculation of the mean free path for each individual photon before scattering, since it involves a complex numerical integration over the scattering cross section and the (thermal) velocity distribution of the scattering electrons. We aim to numerically calculate interpolation tables which can be used in CRSF simulations to sample the mean free path of the scattering photon and the momentum of the scattering electron. The tables also contain all the information required for sampling the scattering electron's final spin. The tables were calculated using an adaptive Simpson integration scheme. The energy and angle grids were refined until a prescribed accuracy is reached. The tables are used by our simulation code to produce artificial CRSF spectra. The electron momenta sampled during these simulations were analyzed and justified using theoretically determined boundaries. We present a complete set of tables suited for mean free path calculations of Monte Carlo simulations of the cyclotron scattering process for conditions expected in typical X-ray pulsar accretion columns (0.01<B/B_{crit}<=0.12, where B_{crit}=4.413x10^{13} G and 3keV<=kT<15keV). The sampling of the tables is chosen such that the results have an estimated relative error of at most 1/15 for all points in the grid. The tables are available online at http://www.sternwarte.uni-erlangen.de/research/cyclo.Comment: A&A, in pres

The XMM-Newton view of the Crab

Aims. We discuss the current X-ray view of the Crab Nebula and Pulsar, summarising our analysis of observations of the source with the EPIC-pn camera on board the XMM-Newton observatory. Different modes of EPIC-pn were combined in order to yield a complete scenario of the spectral properties of the Crab resolved in space and time (pulse phase). In addition we give a description of the special EPIC-pn Burst mode and guidance for data reduction in that mode. Methods. We analysed spectra for the nebula and pulsar separately in the 0.6−12.0 keV energy band. All data were processed with the SAS 6.0.0 XMM-Newton Scientific Analysis System package; models were fitted to the data with XSPEC 11. The high time resolution of EPIC-pn in its Burst mode (7 μs) was used for a phase resolved analysis of the pulsar spectrum, after determination of the period with epoch folding techniques. Data from the SmallWindow mode were processed and corrected for pile-up allowing for spectroscopy simultaneously resolved in space and time. Results. The spatial variation of the spectrum over the entire region of the Crab shows a gradual spectral softening from the inner pulsar region to the outer nebula region with a variation in photon index, Γ, from 2.0 to 2.4. Pulse phase resolved spectroscopy of the Crab Pulsar reveals a phase dependent modulation of the photon index in form of a significant hardening of the spectrum in the inter-peak phase from Γ = 1.7 during the pulse peak to Γ = 1.5

Adaptation Algorithm and Theory Based on Generalized Discrepancy

We present a new algorithm for domain adaptation improving upon a discrepancy minimization algorithm previously shown to outperform a number of algorithms for this task. Unlike many previous algorithms for domain adaptation, our algorithm does not consist of a fixed reweighting of the losses over the training sample. We show that our algorithm benefits from a solid theoretical foundation and more favorable learning bounds than discrepancy minimization. We present a detailed description of our algorithm and give several efficient solutions for solving its optimization problem. We also report the results of several experiments showing that it outperforms discrepancy minimization

Particle Ordering in Zero Range Process : Exact spatial correlations of the corresponding exclusion models

A one dimensional exclusion process is introduced where particles hop to a neighbouring vacant site with a rate that depends on the size of the block they belong to. This model is equivalent to a zero range process (ZRP) and shares the same steady state distribution. However positional ordering is lost in this mapping and spatial correlations which depend on position indices can not be calculated directly from the ZRP equivalence. We devise a method to calculate these correlations and illustrate it by reproducing certain known results. Unexplored correlations in some other model systems are also investigated. This method can be generically used to find exact correlations of one dimensional exclusion processes which has ZRP correspondence.Comment: 9 pages, 1 eps figur