Nonlinear Structural Acoustic Control with Shunt Circuit Governed by a Soft-Computing Algorithm

Noise control has gained a lot of attention recently. However, presence of nonlinearities in Signac paths for some applications can cause significant difficulties in the operation of control algorithms. In particular, this problem is common in structural noise control, which uses a piezoelectric shunt circuit. Not only vibrating structures may exhibit nonlinear characteristics, but also piezoelectric actuators. In this paper, active device casing is addressed. The objective is to minimize the noise coming out of the casing, by controlling vibration of its walls. The shunt technology is applied. The proposed control algorithm is based on algorithms from a group of soft computing. It is verified by means of simulations using data acquired from a real object

Active Noise Control Using a Fuzzy Inference System Without Secondary Path Modelling

For many adaptive noise control systems the Filtered-Reference LMS, known as the FXLMS algorithm is used to update parameters of the control filter. Appropriate adjustment of the step size is then important to guarantee convergence of the algorithm, obtain small excess mean square error, and react with required rate to variation of plant properties or noise nonstationarity. There are several recipes presented in the literature, theoretically derived or of heuristic origin. This paper focuses on a modification of the FXLMS algorithm, were convergence is guaranteed by changing sign of the algorithm steps size, instead of using a model of the secondary path. A Takagi-Sugeno-Kang fuzzy inference system is proposed to evaluate both the sign and the magnitude of the step size. Simulation experiments are presented to validate the algorithm and compare it to the classical FXLMS algorithm in terms of convergence and noise reduction

Use of 3D scanners in the industry

W artykule scharakteryzowano zasadę działania trzech rodzajów laserowych skanerów 3D (triangulacyjnego, impulsowego, fazowego). Szczególna uwagę poświęcono skanerom fazowym. W drugiej części artykułu omówiono zastosowanie skanerów fazowych w przemyśle produkcyjnym. Pokazano, że są one doskonałym narzędziem do modelowania stanowisk pracy oraz hal produkcyjnych dla celów analiz ergonomicznych, eliminacji wąskich gardeł, balansowania linii produkcyjnych, a także wdrożenia digitalnego przedsiębiorstwa.In the paper a principle of operation of three types (trig, impulse, phase) of 3D laser scanners is presented. The particular attention is devoted to phase scanners. The idea of taking measurements is shown in Fig. 1. There is also given the comparison of selected impulse and phase scanners. Table 1 contains the most important parameters of these scanners. In the second part of the paper there is discussed the use of phase scanners in the production industry. It is shown that they are an excellent tool for modelling workstations and factory floors in order to perform ergonomic analyses, to eliminate bottlenecks, to balance production lines as well as to implement digital factories. Fig. 2 presents an exemplary effect of scanning, modelling and analysis conducted for an enterprise of the automotive industry. The paper is summarised with the conclusion that phase scanners are suitable for modelling workstations due to their operating speed, however, they are not suggested for taking precise measurements

Formatives Prüfen praktischer Fertigkeiten mit studentischen Prüfern: Qualitätseigenschaften des OSCE Allgemeinmedizin der Medizinischen Fakultät Heidelberg

Background: Objective Structured Clinical Examinations (OSCEs) have become an established examination format at German medical faculties. Medical experts routinely use a summative assessment to evaluate practical and communicative skills, while the use of the OSCE format by student examiners, as a formative examination, remains rather limited.Objective: The formative OSCE program of the Department of General Practice and Implementation Research at the Heidelberg Medical Faculty, which is conducted and evaluated by peer tutors, is examined with regard to its quality criteria and compared with summative OSCEs from other departments. Methods: Difficulties and discriminatory power of individual testing stations were determined for the summative, as well as the formative OSCE, and compared with each other. To assess the reliability of the measurements, an analysis of the data was carried out using the Generalizability theory. In addition, a comparison is made between the assessments of student examiners and second assessments by medical experts.Results: The stations of the formative OSCE show similar difficulties as those of the summative comparison OSCEs (Pform=0.882; Psum=0.845 - 0.902). With respect to measurement reliability, there are no differences between the OSCE in General Medicine and the other subjects. The assessments of student examiners and medical experts correlate highly (r=0.888).Conclusion: The formative OSCE in General Medicine is comparable to the summative comparison formats in terms of its quality criteria. The use of student examiners can be a reliable alternative to medical experts in formative OSCEs.Hintergrund: Objective Structured Clinical Examinations (OSCEs) sind mittlerweile ein etabliertes Prüfungsformat an deutschen medizinischen Fakultäten. Üblicherweise werden darin praktische und kommunikative Fertigkeiten von medizinischen Experten summativ bewertet. Der Einsatz des OSCEs als formatives Prüfungsformat mit studentischen Prüfern findet bislang eher wenig Anwendung.Zielsetzung: Der an der Medizinischen Fakultät Heidelberg im Fach Allgemeinmedizin durchgeführte formative OSCE, der von Peer-Tutoren durchgeführt und bewertet wird, soll hinsichtlich seiner Gütekriterien untersucht und mit denen summativer OSCEs aus anderen Fachbereichen verglichen werden. Methodik: Schwierigkeiten und Trennschärfen der einzelnen Stationen werden für die summativen sowie den formativen OSCE bestimmt und einander gegenübergestellt. Zur Beurteilung der Messzuverlässigkeit wird eine Analyse der Daten mittels der Generalisierbarkeitstheorie durchgeführt. Zusätzlich findet ein Vergleich zwischen den Bewertungen der studentischen Prüfer und Zweitbewertungen medizinischer Experten statt.Ergebnisse: Die Stationen des formativen OSCEs weisen ähnliche Schwierigkeiten wie die der summativen Vergleichs-OSCEs auf (Pform=0.882; Psum=0.845 - 0.902). Bezüglich der Messzuverlässigkeit zeigen sich keine Unterschiede zwischen dem OSCE Allgemeinmedizin und denen der anderen Fächer. Die Bewertungen der studentischen Prüfer und der medizinischen Experten korrelieren hoch (r=0.888).Schlussfolgerung: Der formative OSCE Allgemeinmedizin ist hinsichtlich seiner Qualitätskriterien vergleichbar mit denen der summativen Vergleichsformate. Der Einsatz studentischer Prüfer kann bei formativen OSCEs eine verlässliche Alternative zu medizinischen Experten darstellen