Automatische Klassifikation von Kommunikationsstandards im europäischen 868 MHz Short Range Device-Band

The automatic recognition of the communication standard that is used by a received signal is a crucial task if universal interoperability between incompatible devices is to be ensured. Basically, two different approaches exist for the solution of such problems: Likelihood-based classifiers make use of the detection and estimation theory and are optimal with regards to the probability of correct decisions. However, this approach rarely leads to feasible solutions if the considered signals are highly heterogeneous or the number of unknown signal parameters is large. Closed-form solutions can often only be found using approximations and assumptions. Feature-based classifiers are based on the principles of pattern recognition. Even though this approach is not optimal vis-à-vis the likelihood-based methods, it can reach a probability of misclassification that is close to the optimal solution, as long as the features are developed suitably. Furthermore, there are numerous possibilities of developing such algorithms, which can be devised with the objective to achieve the desired feasibility. In the present work, both approaches are investigated for the automatic classification of six commonly used communication standards in the European 868 MHz band. Initially, both classifiers are developed and verified via Monte-Carlo simulations. Subsequently, the approaches are compared with respect to feasibility, hardware resources required, assumptions made and the probability of correct decisions. Finally, the feature-based classifier is implemented on a prototype and verified by measurements.Die automatische Erkennung des Kommunikationsstandards, auf dem ein empfangenes Signal basiert, ist eine wichtige Aufgabe, wenn universelle Interoperabilität zwischen inkompatiblen Geräten gewährleistet werden soll. Zur Lösung derartiger Problemstellungen gibt es grundsätzlich zwei verschiedene Herangehensweisen: Hypothesentestbasierte Klassifikatoren beruhen auf der Detektions- und Estimationstheorie und sind optimal im Sinne der Wahrscheinlichkeit korrekter Entscheidungen. Jedoch führen diese Ansätze oftmals nicht zu realisierbaren Lösungen, wenn sehr heterogene Signale betrachtet werden oder die Zahl unbekannter Signalparameter groß ist. Geschlossene mathematische Lösungen lassen sich häufig nur durch Näherungen und Annahmen finden. Merkmalsbasierte Klassifikatoren dagegen beruhen auf den Prinzipien der Mustererkennung. Obwohl diese Verfahren im Gegensatz zu den hypothesentestbasierten Ansätzen nicht optimal sind, kann bei geeigneter Wahl der Merkmale eine Fehlerwahrscheinlichkeit nahe dem Optimum erreicht werden. Zudem bestehen bei der Entwicklung solcher Verfahren zahlreiche Freiheitsgrade, so dass diese Klassifikatoren mit Bedacht auf deren Realisierbarkeit erarbeitet werden können. Im Rahmen der vorliegenden Arbeit werden beide Ansätze für die automatische Klassifikation von sechs häufig verwendeten Kommunikationsstandards im europäischen 868 MHz-Band untersucht. Zunächst werden beide Klassifikatoren entwickelt und mittels Monte-Carlo-Simulationen verifiziert. Anschließend werden die Verfahren unter Berücksichtigung der Realisierbarkeit, des zu erwartenden Schaltungsaufwandes, der getroffenen Annahmen und der Wahrscheinlichkeit korrekter Entscheidungen verglichen und gegeneinander abgewogen. Schließlich wird der merkmalsbasierte Ansatz in Form eines Prototyps implementiert und messtechnisch verifiziert

Steam gasification of biomass – Typical gas quality and operational strategies derived from industrial-scale plants

Steam gasification enables the thermochemical conversion of solid fuels into a medium calorific gas that can be utilized for the synthesis of advanced biofuels, chemicals or for heat and power production. Dual fluidized bed (DFB) gasification is at present the technology applied to realize gasification of biomass in steam environment at large scale. Few large-scale DFB gasifiers exist, and this work presents a compilation and analysis of the data and operational strategies from the six DFB gasifiers in Europe. It is shown that the technology is robust, as similar gas quality can be achieved despite the differences in reactor design and operation strategies. Reference con-centrations of both gas components and tar components are provided, and correlations in the data are in-vestigated. In all plants, adjusting the availability and accessibility to the active ash components (K and Ca) was the key to control the gas quality. The gas quality, and in particular the tar content of the gas, can conveniently be assessed by monitored the concentration of CH4 in the produced gas. The data and experience acquired from these plants provide important knowledge for the future development of the steam gasification of biomass

Influence of bed materials on the performance of the Nong Bua dual fluidized bed gasification power plant in Thailand

Bed materials and their catalytic activity are two main parameters that affect the performance of the dual fluidized bed (DFB) gasification system in terms of product gas composition and tar levels. Two sources of bed materials were used for the operation of a commercial DFB gasification system in Thailand, using woodchips as a biomass feedstock. One source of the bed materials was the calcined olivine which had been used in the Gussing Plant, Austria, and the other activated bed material was a mixture of fresh Chinese olivine and used Austrian olivine with additives of biomass ash, calcium hydroxide and dolomite. These bed materials were collected and analysed for morphological and chemical composition using a scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray fluorescence spectroscopy (XRF). The product gas was cleaned in a scrubber to remove tars, from which the samples were collected for gravimetric tar analysis. Its composition data was automatically recorded at the operation site before it entered the gas engine. From the SEM, EDS and XRF analyses, calcium-rich layers around the bed materials were observed on the activated bed material. The inner layers of bed materials collected were homogeneous. Biomass ash, which was generally added to the bed materials, had significant calcium and potassium content. These calcium-rich layers of the bed materials, from the calcium hydroxide, biomass ash and dolomite, influenced system performance, which was determined by observing lower tar concentration and higher hydrogen concentration in the product gas

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles

We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol. We find that the population-averaging methods of SAXS, CLS and UV-Vis have high measurement repeatability and reproducibility, with between-labs variability of 2.6%, 11% and 1.4% respectively. However, results may be significantly biased for reasons including inaccurate material properties whose values are used to compute the number concentration. Particle-counting method results are less reproducibile than population-averaging methods, with measured between-labs variability of 68% and 46% for PTA and spICP-MS respectively. This study provides the stakeholder community with important comparative data to underpin measurement reproducibility and method validation for number concentration of nanoparticles

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles

We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol. We find that the population-averaging methods of SAXS, CLS and UV-Vis have high measurement repeatability and reproducibility, with between-labs variability of 2.6%, 11% and 1.4% respectively. However, results may be significantly biased for reasons including inaccurate material properties whose values are used to compute the number concentration. Particle-counting method results are less reproducibile than population-averaging methods, with measured between-labs variability of 68% and 46% for PTA and spICP-MS respectively. This study provides the stakeholder community with important comparative data to underpin measurement reproducibility and method validation for number concentration of nanoparticles

4MOST : the 4-metre multi-object spectroscopic telescope project in the assembly, integration, and test phase

4MOST is a new high-multiplex, wide-field spectroscopic survey facility under construction for ESO's 4m-VISTA telescope at Paranal, Chile. Its key specifications are: a large field of view of 4.4 square degrees, a high multiplex fibre positioner based on the tilting spine principle that positions 2436 science fibres in the focal surface of which 1624 fibres go to two low-resolution optical spectrographs (R = λ/Δλ ~ 6500) and 812 fibres transfer light to the high-resolution optical spectrograph (R ~ 20,000). Currently, almost all subsystems are completed and full testing in Europe will be finished in spring 2023, after which 4MOST will be shipped to Chile. An overview is given of instrument construction and capabilities, the planned science of the consortium and the recently selected community programmes, and the unique operational scheme of 4MOST

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles

We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol. We find that the population-averaging methods of SAXS, CLS and UV-Vis have high measurement repeatability and reproducibility, with between-labs variability of 2.6%, 11% and 1.4% respectively. However, results may be significantly biased for reasons including inaccurate material properties whose values are used to compute the number concentration. Particle-counting method results are less reproducibile than population-averaging methods, with measured between-labs variability of 68% and 46% for PTA and spICP-MS respectively. This study provides the stakeholder community with important comparative data to underpin measurement reproducibility and method validation for number concentration of nanoparticles

-

Die automatische Erkennung des Kommunikationsstandards, auf dem ein empfangenes Signal basiert, ist eine wichtige Aufgabe, wenn universelle Interoperabilität zwischen inkompatiblen Geräten gewährleistet werden soll. Zur Lösung derartiger Problemstellungen gibt es grundsätzlich zwei verschiedene Herangehensweisen: Hypothesentestbasierte Klassifikatoren beruhen auf der Detektions- und Estimationstheorie und sind optimal im Sinne der Wahrscheinlichkeit korrekter Entscheidungen. Jedoch führen diese Ansätze oftmals nicht zu realisierbaren Lösungen, wenn sehr heterogene Signale betrachtet werden oder die Zahl unbekannter Signalparameter groß ist. Geschlossene mathematische Lösungen lassen sich häufig nur durch Näherungen und Annahmen finden. Merkmalsbasierte Klassifikatoren dagegen beruhen auf den Prinzipien der Mustererkennung. Obwohl diese Verfahren im Gegensatz zu den hypothesentestbasierten Ansätzen nicht optimal sind, kann bei geeigneter Wahl der Merkmale eine Fehlerwahrscheinlichkeit nahe dem Optimum erreicht werden. Zudem bestehen bei der Entwicklung solcher Verfahren zahlreiche Freiheitsgrade, so dass diese Klassifikatoren mit Bedacht auf deren Realisierbarkeit erarbeitet werden können. Im Rahmen der vorliegenden Arbeit werden beide Ansätze für die automatische Klassifikation von sechs häufig verwendeten Kommunikationsstandards im europäischen 868 MHz-Band untersucht. Zunächst werden beide Klassifikatoren entwickelt und mittels Monte-Carlo-Simulationen verifiziert. Anschließend werden die Verfahren unter Berücksichtigung der Realisierbarkeit, des zu erwartenden Schaltungsaufwandes, der getroffenen Annahmen und der Wahrscheinlichkeit korrekter Entscheidungen verglichen und gegeneinander abgewogen. Schließlich wird der merkmalsbasierte Ansatz in Form eines Prototyps implementiert und messtechnisch verifiziert.The automatic recognition of the communication standard that is used by a received signal is a crucial task if universal interoperability between incompatible devices is to be ensured. Basically, two different approaches exist for the solution of such problems: Likelihood-based classifiers make use of the detection and estimation theory and are optimal with regards to the probability of correct decisions. However, this approach rarely leads to feasible solutions if the considered signals are highly heterogeneous or the number of unknown signal parameters is large. Closed-form solutions can often only be found using approximations and assumptions. Feature-based classifiers are based on the principles of pattern recognition. Even though this approach is not optimal vis-à-vis the likelihood-based methods, it can reach a probability of misclassification that is close to the optimal solution, as long as the features are developed suitably. Furthermore, there are numerous possibilities of developing such algorithms, which can be devised with the objective to achieve the desired feasibility. In the present work, both approaches are investigated for the automatic classification of six commonly used communication standards in the European 868 MHz band. Initially, both classifiers are developed and verified via Monte-Carlo simulations. Subsequently, the approaches are compared with respect to feasibility, hardware resources required, assumptions made and the probability of correct decisions. Finally, the feature-based classifier is implemented on a prototype and verified by measurements