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An important preprocessing step for several music signal processing algorithms is the estimation of playing instruments in music recordings. To this aim, time-dependent instrument recognition is realized by a neural network with residual blocks in this approach. Since music signal processing tasks use diverse time-frequency representations as input matrices, the influence of different input representations for instrument recognition is analyzed in this work. Three-dimensional inputs of short-time Fourier transform (STFT) magnitudes and an additional time-frequency representation based on phase information are investigated as well as two-dimensional STFT or constant-Q transform (CQT) magnitudes. As additional phase representations, the product spectrum (PS), based on the modified group delay, and the frequency error (FE) matrix, related to the instantaneous frequency, are used. Training and evaluation processes are executed based on the MusicNet dataset, which enables the estimation of seven instruments. With a higher number of frequency bins in the input representations, an improved instrument recognition of about 2 % in F1-score can be achieved. Compared to the literature, frame-level instrument recognition can be improved for different input representations.

Time-dependent estimation of playing instruments in music recordings is an important preprocessing for several music signal processing algorithms. In this approach, instrument recognition is realized by neural networks with a two-dimensional input of short-time Fourier transform (STFT) magnitudes and a time-frequency representation based on phase information. The modified group delay (MODGD) function and the product spectrum (PS), which is based on MODGD, are analysed as phase representations. Training and evaluation processes are executed based on the MusicNet dataset. By the incorporation of PS in the input, instrument recognition can be improved about 2% in F1-score.

Microstructures were ablated using an ultra-short pulse laser system in order to investigate the influence of focal position on the surface topography. In addition, acoustic emissions measured by a piezoelectric sensor adapted to the AISI 4140 workpiece were analyzed and correlated with the focal position and the resulting surface topography. Frequency ranges sensitive to variations of the z-axis position were determined by STFT analysis. Subsequently, significant signal components were processed to enable an inference about the focal position. The hypothesis of assessing the focal position in-process based on acoustic emissions to ensure high precision during laser ablation could be confirmed.

FEM chip formation simulations and machining tests of orthogonal cutting were undertaken in order to investigate the influence of cutting speed and tool wear on cutting force, chip segmentation frequency, and residual stress state for Ti-6Al-4V. In addition, acoustic emissions, measured by a piezoelectric sensor adapted to the tool shank, were analyzed to extract chip segmentation frequency in-process using time-frequency representations and periodograms. Results show the capability of robust chip segmentation frequency measuring. The hypothesis of compensating the negative effect of tool wear on the component’s residual stress state by means of targeted adjustment of process parameters can be derived.

Zusammenfassung Aus einem polyphonen Musiksignal mit mehreren gleichzeitig klingenden Instrumenten werden die zu einzelnen Noten gehörenden Töne mithilfe eines harmonischen Matching-Pursuit-Algorithmus (HMPA) separiert. Hierfür wird im ersten Schritt des Verfahrens die für den Matching-Pursuit-Algorithmus notwendige Bibliothek auf Basis des vorliegenden Musiksignals aufgebaut. Im zweiten Schritt werden die in der Bibliothek hinterlegten Notenmodelle zur Approximation des Musiksignals verwendet. Anschließend lassen sich die einzelnen Noten aus der Approximation extrahieren und mit dem Vorwissen von Melodieverläufen zu separierten Melodien einzelner Instrumente zusammenfassen.

Economists and policy makers often emphasise the importance of human capital as a key determinant in the pursuit of economic growth. The highest formal qualification in the educational system is the doctorate, which is attained after the first stage of tertiary education at ISCED 6 level. Doctorate holders play a central role in research and innovation in any industrialised economy, with highly specialised knowledge and research capabilities acquired during their studies. However, their employment depends on the availability of suitable positions on the labour market. Despite huge demand for relevant employment data for this particular group, the available data in most countries is scant. The data collection on Careers of Doctorate Holders (CDH) initiated by EUROSTAT, the OECD and the UNESCO somewhat clarifies the professional situation of doctorate holders. This article presents some key findings of the Austrian CDH data collection carried out in 2006–07. The results are, amongst other things, that in Austria the general employment situation of doctorate holders is relatively good. However, they are faced with a shortage of adequate positions, especially in research. Often doctorate holders have to compromise between the intellectual challenge of working in research and the higher job security outside of research. The employment situation and the sectors of employment depend primarily on the field of science and technology of the doctoral degree.

Social and economic changes in urban spaces are the subject of much debate in the area of urban research. This article aims to focus on the spatial aspects of these changes. Using the examples of the eight largest French cities, it shows major changes in the structure of residential segregation between 1968 and 1999. The social space at the beginning of the 21st century is characterised by a new complexity of the urban space, which can no longer be summarised by the three classic dimensions of “social status”, “demographic status”, and “ethnic status” that are traditionally mobilised to describe urban areas. In addition, the study evidences the different processes of redistribution of the population across the urban space, articulating in different manner according to social, demographic and ethnic characteristics of the urban population. Keywords: urban space, social geography, model, residential segregation, gentrification