Track association performance of the best hypotheses search method

Uncontrolled space objects in the geostationary orbit domain are hazardous threats for active satellites. Catalogs need to be build up, in order to protect this precious domain. The Swiss ZimSMART telescope, located in Zimmerwald, regularly scans the geostationary ring in order to provide a homogenous coverage. This surveying technique typically yields short measurement arcs, called tracklets. Each tracklet provides information about the line-of-sight and the rates of change but typically not about the full state of the observed object. Computationally intensive multi-hypothesis filter methods have been developed to associate tracklets with each other. An effective implementation to this approach is presented that uses an optimization algorithm to reduce the number of initial hypotheses. The method is tested with a set of real measurements of the aforementioned telescope

Large-scale Ridesharing DARP Instances Based on Real Travel Demand

Accurately predicting the real-life performance of algorithms solving the Dial-a-Ride Problem (DARP) in the context of Mobility on Demand (MoD) systems with ridesharing requires evaluating them on representative instances. However, the benchmarking of state-of-the-art DARP solution methods has been limited to small, artificial instances or outdated non-public instances, hindering direct comparisons. With the rise of large MoD systems and the availability of open travel demand datasets for many US cities, there is now an opportunity to evaluate these algorithms on standardized, realistic, and representative instances. Despite the significant challenges involved in processing obfuscated and diverse datasets, we have developed a methodology using which we have created a comprehensive set of large-scale demand instances based on real-world data. These instances cover diverse use cases, one of which is demonstrated in an evaluation of two established DARP methods: the insertion heuristic and optimal vehicle-group assignment method. We publish the full results of both methods in a standardized format. The results show significant differences between areas in all measured quantities, emphasizing the importance of evaluating methods across different cities.Comment: 8 pages, 9 figures. Submitted to 26th IEEE International Conference on Intelligent Transportation Systems ITSC 2023. For the published associated dataset and source codes, see the repository https://github.com/aicenter/Ridesharing_DARP_instance

Loss factor estimation of the layered panels

The loss factor identification is the effective way to get the proper acoustic analysis in the virtual environment. Using the predictive model is a necessary part of the virtual development. The detection of the inappropriate materials or malfunction designs in the early phase of product development and can dramatically save the cost and development time. The loss factor is the nonlinear parameter for the material modeling of the noise suppression during acoustic analysis. The identification of the loss factor is necessary to perform on the real specimen. The Decay Rate Method is the effective methodology to get accurate results by using standard measuring equipment and is ideal to use in-situ environment. The article describes loss factor identification for plywood material and applications for the automotive industry for glass materials. The complete results analysis is confidential, but the overall procedure of the method is described in specimen analysis

Loss factor estimation of the plywood materials

The acoustic analysis in virtual environment enables the design optimization in the earlier phase of the new product development in term of the noise suppression of the structure. The structural material damping behavior is the most important parameter for the predictive acoustic simulations. The method for the damping loss factor identification involves the measurement of the real specimen and post-processing analysis. The result of the estimation is the structural damping behavior of plywood materials needed for the virtual acoustic analysis

Elektrische und strukturelle Eigenschaften von supraleitenden Schichten in Gallium- implantiertem Silizium und Germanium

In this work, a pioneering attempt to analyze the influence of superconducting gallium-rich precipitates on the electrical transport properties of heavily-doped silicon and germanium layers is presented. An innovative path for the fabrication of superconducting layers in commercial silicon and germanium wafers by ion implantation and short term annealing is demonstrated. Ion implantation via a thin dielectric cover layer was used to introduce a gallium concentration far above the equilibrium solid solubility limit into the silicon and germanium layers. To initiate the redistribution of the implanted gallium, rapid thermal annealing was subsequently employed. The redistribution of the gallium was investigated and the formation of 10 nm thin gallium-rich layers at the cover layer/semiconducting interface was observed. A new model describing the redistribution mechanism was proposed. It has been observed, that for gallium concentrations at the interface exceeding a critical value of 15 at.%, the layers could become superconducting at temperatures below 6 – 7 K. This critical temperature is comparable to formerly studied thin amorphous gallium films. Therefore, for the first time it is demonstrated, that gallium-rich precipitates lead a critical temperature comparable to that of amorphous gallium. With increasing annealing time superconductor insulator transition was observed. Such transitions are often studied as function of layer thickness. Following the data available in the literature, this phase transition is connected to the normal state sheet resistance. As gallium-rich precipitates are hard to detect in germanium due to the small differences in mass and electronic structure, the structural investigations focus on the silicon layers. Most results of this model system can be transferred to the properties of gallium in germanium. This comparison shows that only the critical temperature of the gallium-rich layers does not depend on the substrate material. Up to now, superconductivity in gallium-doped germanium was only observed at temperatures below 1 K. Based on the results presented in this thesis it can be concluded, that the critical temperature of the superconducting state in gallium-doped germanium is a suitable parameter to distinguish between a doping related superconducting state and superconductivity because of gallium clusters.Zielstellung der Dissertation ist die detaillierte Analyse der Auswirkungen von supraleitenden Galliumausscheidungen auf das elektrische Transportverhalten hochdotierter Silizium- und Germaniumschichten. Dafür wird ein neues Verfahren zur Herstellung von supraleitenden Schichten in kommerziellen Silizium- und Germanium-Wafern mit Hilfe von Ionenimplantation und Kurzzeitausheilung entwickelt. Mittels Ionenimplantation durch eine dünne dielektrische Deckschicht wurden Galliumkonzentrationen weit über der Gleichgewichtslöslichkeit in die Silizium- und Germaniumsubstrate eingebracht. Kurzzeitausheilverfahren wurden verwendet, um die die Umverteilung des Galliums anzuregen. Die resultierende Galliumverteilung wurde analysiert und es konnte ein Modell entwickelt werden, welches die Ursache für die Ausbildung einer 10 nm dünnen Gallium-reichen Schichten an der Deckschicht/Halbleiter-Grenzfläche beschreibt. Übersteigt die Galliumkonzentration an der Grenzfläche den kritischen Wert von 15 at.%, können die Schichten bei Temperaturen unterhalb von 6 – 7 K supraleitend werden und zeigen damit eine ähnlich kritische Temperatur wie bereits untersuchte dünne amorphe Galliumfilme. Es wird somit erstmalig gezeigt, dass Gallium-reiche Ausscheidungen eine mit reinem Gallium vergleichbare kritische Temperatur haben. Der bisher häufig als Funktion der Schichtdicke erforschte Supraleiter-Isolator-Übergang konnte in den Schichten durch die Variation der Ausheilzeit hervorgerufen werden. Der normalleitende Schichtwiderstand ist als entscheidender Parameter für den Phasenübergang anzusehen. Da sich Gallium-reiche Ausscheidungen in Germanium wegen der geringen Differenz in Masse und Elektronenstruktur nur schwer nachweisen lassen, erfolgten die Strukturuntersuchungen hauptsächlich an Siliziumschichten. Die Ergebnisse dieses Modellsystems lassen sich zum großen Teil auf das Verhalten von Gallium in Germanium übertragen. Dieser Vergleich zeigt, dass außer der kritischen Temperatur alle elektrischen Eigenschaften der Gallium-reichen Schichten vom Substratmaterial abhängen. Supraleitung in Gallium-dotiertem Germanium wurde bisher nur bei Temperaturen unterhalb von 1 K beobachtet. Deshalb ist die kritische Temperatur ein geeigneter Parameter, um durch Dotierung hervorgerufene Supraleitung in Germanium von supraleitenden Ausscheidungen zu unterscheiden

Changes in biological monitoring of running waters using benthos with respect to diatoms

This work focuses on the development of a methodological approach to biomonitoring of running waters using benthic organisms. It discusses the development from methods focused on determining organisms by their external appearance to modern biomonitoring based on the determination of organisms by eDNA metabarcoding. Modern metagenomic methods (genomics, transcriptomics, metabolomics and proteomics) are also mentioned. This thesis compares the development of ecological status assessment of freshwater ecosystems using diatoms and invertebrates. It also describes the common points of their methodological development. Another outcome of the comparison is information on which hydrochemical and geochemical environmental factors can be easily monitored by diatoms and which by macroscopic invertebrates. Furthermore, a prognosis for the further development of biomonitoring is mentioned in the conclusion. It is formulated as a synthesis of traditional methods based on morphological species determination, biomonitoring 2.0 (using eDNA metabarcoding) and metagenomic methods. Key words: autecology, morphospecies, sequencing, biotic index, pollutionTato práce je zaměřena na vývoj metodologického přístupu k biomonitoringu tekoucích vod pomocí bentických organismů od metod zaměřených na určování organismů pomocí jejich vnějšího vzhledu až k modernímu biomonitoringu založenému na determinaci organismů pomocí eDNA metabarcodingu. V práci jsou zmíněny také moderní metagenomické metody (genomika, transkriptomika, metabolomika a proteomika). Práce srovnává vývoj hodnocení ekologického stavu sladkovodních ekosystémů pomocí rozsivek a bezobratlých a popisuje shodné body metodologického vývoje obou. Dalším výstupem porovnání biomonitoringu pomocí dvou různých taxonomických skupin jsou informace o tom, které hydrochemické a geochemické faktory prostředí lze snadno monitorovat pomocí rozsivek a které pomocí makroskopických bezobratlých. Dále je v závěru zmíněna prognóza dalšího vývoje biomonitoringu v podobě syntézy tradičních metod na základě morfologické determinace druhů, biomonitoringu 2.0 (využívajícího eDNA metabarcoding) a metagenomických metod. Klíčová slova: autekologie, morfologicky definované druhy, sekvenování, biotický index, znečištěníDepartment of BotanyKatedra botanikyFaculty of SciencePřírodovědecká fakult

Causes of steam turbine malfunction

Příspěvek se zabývá nejčastějšími příčinami poruch parních turbín z pohledu soudního znalce. Pečlivá analýza poruch a havárií je důležitým faktorem zvyšování spolehlivosti provozu parních turbín a mají o ni zájem jak provozovatelé, tak zejména výrobci parních turbín. Autor analyzuje poruchy na skutečných případech, které řešil a hledá kořenové příčiny jejich vzniku. Současně rozebírá možnosti, jak eliminovat podobné havárie v budoucnosti. Závěrem uvádí několik vlastních obecných poznatků ze své praxe.The paper deals with the most common causes of steam turbine malfunction from the point of view of a court expert. Careful analysis of failures and accidents is an important factor in increasing the reliability of steam turbine operation and is of interest to both operators and steam turbine manufacturers. The author analyses the malfunctions in the real cases he solved and looks for the root causes of their occurrence. At the same time, he discusses ways to eliminate similar accidents in the future. In conclusion, he presents some of his own general findings he collected during his practice as a court expert

Isomeric separation in donor–acceptor systems of Pd(II) and Pt(II) and a combined structural, electrochemical and spectroelectrochemical study

Compounds of the form [(pap)M(Q2−)] (pap = phenylazopyridine; Q = 3,5-di-tert- butyl-benzoquinone, M = Pd, 1a and 1b, M = Pt, 2a and 2b; Q = 4-tert-butyl- benzoquinone, M = Pd, 3a and 3b; M = Pt, 4a and 4b) were synthesized in a one- pot reaction. The geometrical isomers, which are possible because of the built in asymmetry of these ligands, have been separated by using different temperatures and variable solubility. Structural characterization of 1b shows that the metal centers are in a square planar environment, the pap ligand is in the unreduced neutral state and the quinones are in the doubly reduced, Q2−catecholate form. Cyclic voltammetric measurements on the complexes display two one-electron oxidations and two one-electron reductions. EPR and vis-NIR spectra of the one-electron oxidized forms of the complexes indicate that the first oxidation takes place on the Q2− ligands to produce a metal bound semiquinone (Q˙−) radical. Reduction takes place on the pap ligand, generating metal bound pap˙− as seen from the 14N (I = 1) coupling in their EPR spectrum. All the complexes in their [(pap)M(Q2−)] neutral forms show strong absorptions in the NIR region which are largely LLCT (ligand to ligand charge transfer) in origin. These NIR bands can be tuned over a wide energy range by varying the metal center as well as the Q ligand. In addition, the intensity of NIR bands can be switched on and off by a simple electron transfer at relatively low potentials. DFT studies were used to corroborate these findings