Objective: To validate an intracoronary Doppler ultrasound device for high intensity transient signals (HITS) detection and to assess the incidence of HITS during percutaneous coronary intervention (PCI). Methods and Results:In an in vitro model, particle count and number of HITS detected by an intracoronary 0.014 inch Doppler wire were closely correlated (r = 0.97, p , 0.001). In the clinical study, 32 patients (mean (SD) age 61 (11) years; 23 men, nine women) with coronary artery disease were treated with balloon dilatation and stent implantation for a single vessel stenosis. In these patients HITS were detected during PCI in 84% (27 of 32). Reproducibility (r = 0.99, p , 0.001) and interobserver agreement (r = 0.84, p , 0.001) of HITS counts were significant. The number of HITS after stent implantation was significantly higher than after balloon dilatation (11 (7) v 2 (4), p , 0.001). Postprocedural coronary flow velocity reserve (CFVR) was , 2.0 in 55% (16 of 29) of all patients after balloon dilatation and , 2.0 in 23% (six of 26) after stent implantation. The number of HITS after stent implantation did not differ significantly between patients with CFVR , 2.0 and patients with CFVR > 2.0 (12 (8) v 10 (7), not significant). Conclusions: Embolic particles can be detected as HITS by an intracoronary Doppler ultrasound device. Coronary microembolism is often observed during PCI, especially after stent implantation. However, the incidence of HITS alone does not explain a reduced CFVR after PCI.

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Previously proposed methods for fast channel change include use special codec features (e.g., switching frames or adaptive playback) and approaches based on special content delivery infrastructure (e.g., edge servers). However, to have a basis of comparison, we have to answer the question: what is actually achievable by streaming with standard encoding and transport without additional infrastructure other than multicast? We derive lower limits for the channel change time that are achievable with multicast transport for a given bandwidth. This limit can be further reduced arbitrarily by using additional infrastructure.

Today, many applications such as production or rescue settings rely on highly accurate entity positioning. Advanced Time of Flight (ToF) based positioning methods provide highaccuracy localization of entities. A key challenge for ToF based positioning is to synchronize the clocks between the participating entities. This paper summarizes and analyzes ToA and TDoA methods with respect to clock error robustness. The focus is on synchronization-less methods, i.e. methods which reduce the infrastructure requirement significantly. We introduce a unified notation to survey and compare the relevant work from literature. Then we apply a clock error model and compute worst case location-accuracy errors. Our analysis reveals a superior error robustness against clock errors for so called Double-Pulse methods when applied to radio based ToF positioning.

Many applications require positioning. Time of Flight (ToF) methods calculate distances by measuring the propagation time of signals. We present a novel ToF localization method. Our new approach works infrastructure-less, without pre-defined roles like Anchors or Tags. It generalizes existing synchronization-less Time Difference of Arrival (TDoA) and Time of Arrival (ToA) algorithms. We show how known algorithms can be derived from our new method. A major advantage of our approach is that it provides a comparable or better clock error robustness, i.e. the typical errors of crystal oscillators have negligible impact for TDoA and ToA measurements. We show that our channel usage is for most cases superior compared to the state-of-the art.

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