Lärmempfindlichkeit und mobiles Musikhören im urbanen Umfeld

Während die Weltgesundheitsorganisation schon seit geraumer Zeit auf die negativen Auswirkungen von Lärm hinweist, sind nach wie vor viele Menschen im Wohnumfeld und auch im öffentlichen Raum hohen Lärmpegeln ausgesetzt. Ob Musik im Umgang mit Umweltlärm genutzt wird und welche Zusammenhänge mit der individuellen Lärmempfindlichkeit im urbanen Raum bestehen, sollte im Rahmen der vorliegenden Studie untersucht werden. Dazu wurde ein Online-Fragebogen erstellt, der neben der Häufigkeit des mobilen Musikhörens auch das Motiv des bewussten Lärmausblendens und das Hörverhalten sowie die individuelle Lärmempfindlichkeit erfasste. Die Ergebnisse von 149 Befragten zeigen, dass diejenigen Personen, die empfindlicher auf Lärm reagieren, unterwegs und auch allgemein weniger Musik hören als weniger lärmempfindliche Personen. Wenn lärmempfindliche Personen unterwegs Musik hören, dann jedoch häufiger als andere, um sich von störenden Geräuschen abzuschotten. Kopfhörer mit lärmabschottender Wirkung (Noise-Cancelling, Over-Ears, In-Ears) wurden von 107 der Befragten verwendet, wobei lärmempfindliche Personen diese Art der Kopfhörer nicht häufiger nutzten. Die Bedeutung der Lärmempfindlichkeit für das Musikhörverhalten im urbanen Raum steht im Zusammenhang mit mehreren Faktoren, die weiterführende Untersuchungen unter Einbeziehung von Pegelmessungen und situativ empfundener Lärmbelastung empfehlen lassen.

Key requirements of a video-call system in a critical care department as discovered during the rapid development of a solution to address COVID-19 visitor restrictions

The COVID-19 pandemic necessitated stringent visitor restrictions in critical care departments worldwide, creating challenges in keeping family members connected to patients and clinical staff. Previous studies have examined how hospitals addressed this challenge by repurposing existing tele-ICU systems or by using personal smartphones as a workaround and have analyzed clinical and family feedback. This case report addresses the experience of rapidly implementing a video-call system in the critical care department of a tertiary referral hospital that had no prior video-call system in place, detailing the key requirements in that setting. The 24 requirements were identified via interviews and surveys to both clinical and technical professionals. The top requirements identified were sound and video quality, usability for clinical staff, call control by staff, and patient privacy. From tailoring a video-call solution for this setting, we learned that video-endpoint selection is a key design decision. The initial proposal was to use wireless tablets, but the selection of a large wired video-endpoint allowed us to better address the requirements in the critical care setting. This was based on several characteristics of the large wired video-endpoint, including: high-fidelity video and sound, with directional noise-cancelling; large touch-screen setup for minimal-click navigation; wired as well as wireless connectivity.

Improved Noise Cancelling Algorithm for Electrocardiogram Based on Moving Average Adaptive Filter

The electrocardiogram (ECG) is basic equipment used in the diagnosis of cardiac illness. However, in non-developed countries, most of the population does not have access to medical tests, and many hospitals do not even have these ECGs. On the other hand, the electrical signals generated by the heart and acquired by the ECG have low power and are affected by electromagnetic interference (EMI), mainly produced by the electrical system. Filtering EMI when frequency varies is a challenging task. Within this context, this work aims to produce an easy-to-use low-cost ECG with good electromagnetic disturbances rejection. The proposed noise rejection system is composed of two moving average filters and a phase-locked-loop, namely 2MAV-PLL. The system operates with a low sampling frequency and attenuates the EMI noise present in the ECG signal regardless of the amplitude, obtaining a filtered signal with a 44-dB signal–noise ratio (SNR) between the frequencies of± 10 Hz of the fundamental frequency. Simulation and experimental results prove that the ECG system can attenuate the EMI using relatively low sampling frequency, giving adequate information for health professionals to properly evaluate an electrocardiogram.

Hybrid Carrier Frequency Modulation Based on Rotor Position to Reduce Sideband Vibro-Acoustics in PMSM Used by Electric Vehicles

In the permanent magnet synchronous motor (PMSM) drive system, the unwilling and ear-piercing vibro-acoustics caused by high-frequency sideband harmonics becomes unacceptable in electric vehicle applications. In this paper, a modified space vector pulse width modulation (SVPWM) technique implemented with a hybrid carrier frequency modulation (HCFM) is provided to reduce the sideband current harmonic components and vibro-acoustic responses. The principle and implementation of the proposed HCFM technique are firstly presented in which the fixed carrier frequency is improved with the sawtooth and random signal-based coupling modulation based on the rotor position. The analytical derivations with the power spectral density method are also proposed. For verification, the experiment tests are conducted on a prototype 12/10 PMSM and microcontroller unit. The effectiveness of the HCFM technique can hence be confirmed considering the sideband vibro-acoustics reduction operated more effectively than that in a conventional random PWM. The proposed approach may provide a new route in noise-cancelling and electromagnetic compatibility for the electric drive powertrain.

Hybrid Carrier Frequency Modulation Based on Rotor Position to Reduce Sideband Vibro-acoustics in PMSM Used by Electric Vehicle

In the permanent magnet synchronous motor (PMSM) drive system, the unwilling and ear-piercing vibro-acoustics caused by high-frequency sideband harmonics becomes unacceptable in the electric vehicle application. In this paper, a modified space vector pulse-width modulation (SVPWM) technique implemented with hybrid carrier frequency modulation (HCFM) is provided to reduce the sideband current harmonic components and vibro-acoustic responses. The principle and implementation of the proposed HCFM technique are firstly presented, in which the fixed carrier frequency is improved with the sawtooth and random signal-based coupling modulation based on the rotor position. For verification, the experiment tests are carried out on a prototype 12/10 PMSM and microcontroller unit. The effectiveness of the HCFM technique can hence be confirmed, in which the sideband vibro-acoustics reduction shows more effectively than that in conventional random PWM. The proposed approach may provide a new route in noise-cancelling and electromagnetic compatibility for the electric drive powertrain.

Study on Control Method of Magnetic Flux Density Waveform in AC Magnetic Measurement

To estimate the magnetic properties of the magnetic material, magnetic flux density waveform (B waveform) must be sinusoidal wave. However, it is necessary to control the exciting waveform in consideration of the distortion, because voltage waveform induced by B-coil is distorted due to the magnetic properties. As a result, the IBCM can make B waveform sinusoidal wave with the least number of feedbacks than any control method. Because the IBCM performs noise cancelling for measured waveform and make accurate exciting waveform from measured waveform.