84 research outputs found
RECOGNITION OF SPORTS EXERCISES USING INERTIAL SENSOR TECHNOLOGY
Supervised learning as a sub-discipline of machine learning enables the recognition of correlations between input variables (features) and associated outputs (classes) and the application of these to previously unknown data sets. In addition to typical areas of application such as speech and image recognition, fields of applications are also being developed in the sports and fitness sector. The purpose of this work was to implement a workflow for the automated recognition of sports exercises in the Matlab® programming environment and to carry out a comparison of different model structures. First, the acquisition of the sensor signals provided in the local network and their processing were implemented. The functionalities to be realised included the interpolation of lossy time series, the labelling of the activity intervals performed and, in part, the generation of sliding windows with statistical parameters. The preprocessed data were used for the training of classifiers and artificial neural networks (ANN). These were iteratively optimised in their corresponding hyper parameters for the data structure to be learned. The most reliable models were finally trained with an increased data set, validated and compared with regard to the achieved performance. In addition to the usual evaluation metrics such as F1 score and accuracy, the temporal behaviour of the assignments was also displayed graphically, which enabled statements to be made about potential causes for incorrect assignments. In this context, especially the transition areas between the classes were detected as erroneous assignments as well as exercises with insufficient or clearly deviating execution. The best overall accuracy achieved with ANN and the increased dataset was 93.7 %
Time-based parameter identification and controller design for motion control systems
Today, a cascaded system of position loop, velocity loop and current loop is standard in industrial motion controllers. Each controller has to be designed according to its subordinated system behavior. Usually, the controller commissioning is realized in the frequency domain with the open-loop frequency response. In contrast to that, several tuning rules in the time domain are applicable, which require a model of the plant. The paper presents a method for the identification of plant parameters in the time domain. The approach is based on the auto relay feedback experiment by Åström/ Hägglund and a modified technique of gradual pole compensation. In addition to a theoretical description, the paper presents the implementation as an automatic application in the motion control system SIMOTION. Finally, the velocity controller is adjusted with various tuning rules. Furthermore, the identification results as well as the achievable controller performance on a test rig will be presented
Energy efficiency measures for drive cooling system of a machine tool by use of physical simulation models
IMU Data-based Recognition for Sports Exercises: An Enhanced Distance Optimization Approach for Repetition Counting ​Across Activities
In the field of human activity recognition (HAR), inertial measurement units (IMUs) are a commonly used method to record movement patterns. In the study presented in this paper, IMU captured seven different sports exercises performed by 21 participants. In the preliminary data analysis phase, an exercise classification was conducted using the Long Short Term Memory (LSTM) Network and Temporal Convolutional Network (TCN). The LSTM achieved an accuracy rate of 94.2 % for training and 90.8 % for testing. Similarly, the TCN demonstrated rates of 95.5 % for training and 91.6 % for testing. The subsequent stage was centered on quantifying the number of completed repetitions. A distance value was derived which showed promising results for exercise-independent counting without the need for manual feature selection. For further improvement, a range-to-mean ratio of the standard deviation was calculated and used for feature selection. Combined with a local extrema analysis of the modified distance values the accuracy of counting repetitions was significantly improved, especially for exercises that show irregularities in the signal course
Isolation of Brucella inopinata from a White’s tree frog (Litoria caerulea): pose exotic frogs a potential risk to human health?
IntroductionCold-blooded hosts, particularly exotic frogs, have become a newly recognized reservoir for atypical Brucella species and strains worldwide, but their pathogenicity to humans remains largely unknown. Here we report the isolation and molecular characterization of a B. inopinata strain (FO700662) cultured from clinical samples taken from a captive diseased White’s Tree Frog (Litoria caerulea) in Switzerland. The isolation of B. inopinata from a frog along with other reports of human infection by atypical Brucella raises the question of whether atypical Brucella could pose a risk to human health and deserves further attention.MethodsThe investigations included histopathological analysis of the frog, bacterial culture and in-depth molecular characterization of strain FO700662 based on genome sequencing data.Results and DiscussionOriginally identified as Ochrobactrum based on its rapid growth and biochemical profile, strain FO700622 was positive for the Brucella- specific markers bcsp31 and IS711. It showed the specific banding pattern of B. inopinata in conventional Bruce-ladder multiplex PCR and also had identical 16S rRNA and recA gene sequences as B. inopinata. Subsequent genome sequencing followed by core genome-based MLST (cgMLST) analysis using 2704 targets (74% of the total chromosome) revealed only 173 allelic differences compared to the type strain of B. inopinata BO1T, while previously considered the closest related strain BO2 differed in 2046 alleles. The overall average nucleotide identity (ANI) between the type strain BO1T and FO700622 was 99,89%, confirming that both strains were almost identical. In silico MLST-21 and MLVA-16 also identified strain FO700662 as B. inopinata. The nucleotide and amino acid-based phylogenetic reconstruction and comparative genome analysis again placed the isolate together with B. inopinata with 100% support. In conclusion, our data unequivocally classified strain FO700622, isolated from an exotic frog, as belonging to B. inopinata
The ACS Fornax Cluster Survey. IX. The Color-Magnitude Relation of Globular Cluster Systems
We investigate the color-magnitude relation for globular clusters (GCs) --
the so-called "blue tilt" -- detected in the ACS Fornax Cluster Survey and
using the combined sample of GCs from the ACS Fornax and Virgo Cluster Surveys.
We find a tilt of gamma_z=d(g-z)/dz=-0.0257 +- 0.0050 for the full GC sample of
the Fornax Cluster Survey (~5800 GCs). This is slightly shallower than the
value gamma_z=-0.0459 +- 0.0048 found for the Virgo Cluster Survey GC sample
(~11100 GCs). The slope for the merged Fornax and Virgo datasets (~16900 GCs)
is gamma_z=-0.0293 +- 0.0085, corresponding to a mass-metallicity relation of Z
~ M^0.43. We find that the blue tilt sets in at GC masses in excess of M ~
2*10^5 M_sun. The tilt is stronger for GCs belonging to high-mass galaxies (M_*
> 5 * 10^10 M_sun) than for those in low-mass galaxies (M_* < 5 * 10^10 M_sun).
It is also more pronounced for GCs with smaller galactocentric distances. Our
findings suggest a range of mass-metallicity relations Z_GC ~ M_GC^(0.3-0.7)
which vary as a function of host galaxy mass/luminosity. We compare our
observations to a recent model of star cluster self-enrichment with generally
favorable results. We suggest that, within the context of this model, the
proto-cluster clouds out of which the GCs formed may have had density profiles
slightly steeper than isothermal and/or star formation efficiencies somewhat
below 0.3. We caution, however, that the significantly different appearance of
the CMDs defined by the GC systems associated with galaxies of similar mass and
morphological type pose a challenge to any single mechanism that seeks to
explain the blue tilt. We therefore suggest that the merger/accretion histories
of individual galaxies have played a non-negligible role determining the
distribution of GCs in the CMDs of individual GC systems
The Fading Optical Counterpart of GRB~970228, Six Months and One Year Later
We report on observations of the fading optical counterpart of the gamma-ray
burst GRB 970228, made with the Hubble Space Telescope STIS CCD approximately
six months after outburst and with the HST/NICMOS and Keck/NIRC approximately
one year after outburst. The unresolved counterpart is detected by STIS at
V=28.0 +/- 0.25, consistent with a continued power-law decline with exponent
-1.14 +/- 0.05. The counterpart is located within, but near the edge of, a
faint extended source with diameter ~0."8 and integrated magnitude V=25.8 +/-
0.25. A reanalysis of HST and NTT observations performed shortly after the
burst shows no evidence of proper motion of the point source or fading of the
extended emission. Only the extended source is visible in the NICMOS images
with a magnitude of H=23.3 +/- 0.1. The Keck observations find K = 22.8 +/-
0.3. Several distinct and independent means of deriving the foreground
extinction in the direction of GRB 970228 all agree with A_V = 0.75 +/- 0.2.
After adjusting for Galactic extinction, we find that the size of the observed
extended emission is consistent with that of galaxies of comparable magnitude
found in the Hubble Deep Field (HDF) and other deep HST images. Only 2% of the
sky is covered by galaxies of similar or greater surface brightness; therefore
the extended source is almost certainly the host galaxy. Additionally, we find
that the extinction-corrected V - H and V - K colors of the host are as blue as
any galaxy of comparable or brighter magnitude in the HDF. Taken in concert
with recent observations of GRB 970508, GRB 971214, and GRB 980703 our work
suggests that all four GRBs with spectroscopic identification or deep
multicolor broad-band imaging of the host lie in rapidly star-forming galaxies.Comment: 24 pages, Latex, 4 PostScript figures, to appear in the May 10 issue
of The Astrophysical Journal (Note: displayed abstract is abridged
The velocity dispersion and mass function of the outer halo globular cluster Palomar 4
We obtained precise line-of-sight radial velocities of 23 member stars of the
remote halo globular cluster Palomar 4 (Pal 4) using the High Resolution
Echelle Spectrograph (HIRES) at the Keck I telescope. We also measured the mass
function of the cluster down to a limiting magnitude of V~28 mag using archival
HST/WFPC2 imaging. We derived the cluster's surface brightness profile based on
the WFPC2 data and on broad-band imaging with the Low-Resolution Imaging
Spectrometer (LRIS) at the Keck II telescope. We find a mean cluster velocity
of 72.55+/-0.22 km/s and a velocity dispersion of 0.87+/-0.18 km/s. The global
mass function of the cluster, in the mass range 0.55<=M<=0.85 M_solar, is
shallower than a Kroupa mass function and the cluster is significantly depleted
in low-mass stars in its center compared to its outskirts. Since the relaxation
time of Pal 4 is of the order of a Hubble time, this points to primordial mass
segregation in this cluster. Extrapolating the measured mass function towards
lower-mass stars and including the contribution of compact remnants, we derive
a total cluster mass of 29800 M_solar. For this mass, the measured velocity
dispersion is consistent with the expectations of Newtonian dynamics and below
the prediction of Modified Newtonian Dynamics (MOND). Pal 4 adds to the growing
body of evidence that the dynamics of star clusters in the outer Galactic halo
can hardly be explained by MOND.Comment: 17 pages, accepted for publication in MNRAS; Fig. 8 surface
brightness/density data at github.com/matthiasjfrank/pal4_surface_brightnes
Sphingolipid subtypes differentially control proinsulin processing and systemic glucose homeostasis
Impaired proinsulin-to-insulin processing in pancreatic β-cells is a key defective step in both type 1 diabetes and type 2 diabetes (T2D) (refs. ), but the mechanisms involved remain to be defined. Altered metabolism of sphingolipids (SLs) has been linked to development of obesity, type 1 diabetes and T2D (refs. ); nonetheless, the role of specific SL species in β-cell function and demise is unclear. Here we define the lipid signature of T2D-associated β-cell failure, including an imbalance of specific very-long-chain SLs and long-chain SLs. β-cell-specific ablation of CerS2, the enzyme necessary for generation of very-long-chain SLs, selectively reduces insulin content, impairs insulin secretion and disturbs systemic glucose tolerance in multiple complementary models. In contrast, ablation of long-chain-SL-synthesizing enzymes has no effect on insulin content. By quantitatively defining the SL-protein interactome, we reveal that CerS2 ablation affects SL binding to several endoplasmic reticulum-Golgi transport proteins, including Tmed2, which we define as an endogenous regulator of the essential proinsulin processing enzyme Pcsk1. Our study uncovers roles for specific SL subtypes and SL-binding proteins in β-cell function and T2D-associated β-cell failure
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