Danube University Krems

About: Danube University Krems is a education organization based out in Krems, Niederösterreich, Austria. It is known for research contribution in the topics: Stroke & Population. The organization has 498 authors who have published 1572 publications receiving 68797 citations.

Performance of IEEE 802.11’s Timing Advertisement Against Sync TSF for Wireless Clock Synchronization

Abstract: The lack of provisioning of synchronized timing support from known timing standards in IEEE 802.11 wireless networks has been overcome in IEEE 802.11-2012 through the timing advertisement (TA) mechanism. The scheme, however, presents a synchronization architecture of a cascade of four clocks. It provides no information on how the external time will be synchronized with the built-in clock of the access point (AP) and when the timestamping is performed on the wireless link, which can lead to a loss in synchronization accuracy. To this end, this work analyzes the quantitative performance of the TA mechanism with a non-IEEE802.11 mechanism, Sync TSF, which also uses the same four clocks as in the TA mechanism and compares their performance with the help of simulations. Both schemes offer similar accuracy and precision if the offset corrections involved in both schemes are carried out properly. Nevertheless, Sync TSF is more flexible, as it can be easily implemented using commercial off-the-shelf hardware using only software support. For the implementation of TA mechanism, additional guidelines from the IEEE 802.11 Standard along with dedicated hardware support is required.

Towards a Robot for Supporting Older People to Stay Longer Independent at Home

Abstract: The paper presents the intentions and the preliminary findings of the Socially Assistive Robot HOBBIT. The goal is to come up with a robotic solution which will balance user needs, acceptance and technical performance in an economic and affordable way while providing a solution for fall detection and prevention. Falls are the main risk of older adults living alone that require moving from home to care institutions. Hence, it is a primary target area to prevent falls and, if they happen nevertheless, to react immediately to prevent aggravated causes. We present first results of user trials given six tasks with the robot. To show the effect of bonding with the user - Mutual Care - users were separated in two groups. Results indicate that users find the robot more usable in the Mutual Care condition.

Automatic Packing Mechanism for Simplification of the Scheduling in Profinet IRT

Abstract: In order to support very small cycle times, Profinet isochronous real-time (IRT) was improved by implementing the dynamic frame packing (DFP) mechanism. It turned out that DFP is relatively efficient, but it still has two crucial drawbacks. The complex scheduling has to be recalculated every time the network structure is modified. Furthermore, DFP only operates efficiently in line topology. This study presents a proposal for further improvements of Profinet IRT by implementing an automatic packing mechanism (APM). The main advantage of APM lies in the fact that a dedicated scheduling algorithm is not required. Furthermore, APM achieves approximately the same performance as DFP in line topology, but it has a distinctive advance in star or tree topologies. This paper also presents experimental validation results that prove the functionality of the approach. APM could be implemented with only minor modifications of the media access control (MAC) and physical layer (PHY) hardware to improve the flexibility of Profinet IRT.

The imbalance between osteoprotegerin and cathepsin K in the serum of patients with longstanding rheumatoid arthritis.

Abstract: Osteoprotegerin (OPG) and soluble receptor activator of NF-kappa B ligand (sRANKL) together regulate the bone metabolism among other cytokines, whereby cathepsin K has a potent collagen-degrading activity. An imbalance of this system may be partly responsible for the skeletal complications of RA. Expanding on a previous study, we investigated the relationship between OPG, sRANKL and cathepsin K levels in the serum of patients with longstanding RA. We measured serum levels of OPG, sRANKL and cathepsin K of 100 patients with active, longstanding RA. We detected elevated serum levels of cathepsin K (median 54.8 pmol/l) and OPG (median 4.8 pmol/l), but normal sRANKL levels (median 0.2 pmol/l). Cathepsin K did not show a correlation with the overexpressed OPG (P=0.64) and sRANKL (P=0.81). The radiological destruction correlates significantly with cathepsin K (P=0.004) and OPG (P=0.007). We speculate that the increased levels of OPG are effective in compensating the action of sRANKL, but do not directly prevent bone degradation, as reflected by the elevated serum levels of cathepsin K.