Effects of Classroom Noise on Students and Teachers in Greece

2003 ◽  
Vol 96 (2) ◽  
pp. 539-544 ◽  
Author(s):  
Dimitris Skarlatos ◽  
Manolis Manatakis

Measurements inside 32 occupied high-school classrooms during the courses showed that the measured long-term equivalent noise levels are high. A significant percentage of students and teachers found these levels unacceptable. The observed noise levels depend on the time period of the course, the age, and the number of the students in each classroom. The large reverberation time and the high background noise are responsible for the measured high noise level.

2014 ◽  
Vol 1065-1069 ◽  
pp. 1634-1637
Author(s):  
Qian Li ◽  
Dong Sheng Liu

Generally, there is a high background noise and long reverberation time and poor speech intelligibility in exhibition space due to its big crowd and often commercial promotional activities so that communication is very hard, commercial activities broadcasting system is also difficult to ensure that customers can clearly hear the propaganda content. In this paper, through measured background noise of the new exhibition center in Chengdu, we found the acoustic problem in exhibition space, then we did simulation analysis in some exhibition building and took some acoustical process to get a good sound field.


2020 ◽  
Vol 375 (1802) ◽  
pp. 20190471 ◽  
Author(s):  
Heiner Römer ◽  
Marc Holderied

Many insect families have evolved ears that are adapted to detect ultrasonic calls of bats. The acoustic sensory cues indicating the presence of a bat are then used to initiate bat avoidance behaviours. Background noise, in particular at ultrasonic frequencies, complicates these decisions, since a response to the background may result in costly false alarms. Here, we quantify bat avoidance responses of small rainforest crickets (Gryllidae, Trigoniinae), which live under conditions of high levels of ultrasonic background noise. Their bat avoidance behaviour exhibits markedly higher thresholds than most other studied eared insects. Their responses do not qualitatively differ at suprathreshold amplitudes up to sound pressure levels of 105 dB. Moreover, they also exhibit evasive responses to single, high-frequency events and do not require the repetitive sequence of ultrasonic calls typical for the search phase of bat echolocation calls. Analysis of bat and katydid sound amplitudes and peak frequencies in the crickets' rainforest habitat revealed that the cricket's behavioural threshold would successfully reject the katydid background noise. Using measurements of the crickets' echo target strength for bat predators, we calculated the detection distances for both predators and prey. Despite their high behavioural threshold, the cricket prey still has a significant detection advantage at frequencies between 20 and 40 kHz. The low-amplitude bat calls they ignore are no predation threat because even much louder calls would be detected before the bat would hear the cricket echo. This leaves ample time for evasive actions. Thus, a simple decision criterion based on a high-amplitude behavioural threshold can be adaptive under the high background noise levels in nocturnal rainforests, in avoiding false alarms and only missing detection for bat calls too far away to pose a risk. This article is part of the theme issue ‘Signal detection theory in recognition systems: from evolving models to experimental tests’.


2021 ◽  
Vol 150 (2) ◽  
pp. 709-717
Author(s):  
Rebecca A. Hamilton ◽  
Josefin Starkhammar ◽  
Stefanie K. Gazda ◽  
Richard C. Connor

2005 ◽  
Vol 26 (2) ◽  
pp. 100-106 ◽  
Author(s):  
James D.A. Parker ◽  
Donald H. Saklofske ◽  
Laura M. Wood ◽  
Jennifer M. Eastabrook ◽  
Robyn N. Taylor

Abstract. The concept of emotional intelligence (EI) has attracted growing interest from researchers working in various fields. The present study examined the long-term stability (32 months) of EI-related abilities over the course of a major life transition (the transition from high school to university). During the first week of full-time study, a large group of undergraduates completed the EQ-i:Short; 32 months later a random subset of these students (N = 238), who had started their postsecondary education within 24 months of graduating from high school, completed the measures for a second time. The study found EI scores to be relatively stable over the 32-month time period. EI scores were also found to be significantly higher at Time 2; the overall pattern of change in EI-levels was more than can be attributed to the increased age of the participants.


2009 ◽  
Vol 277 (1685) ◽  
pp. 1247-1252 ◽  
Author(s):  
Christina Richardson ◽  
Thierry Lengagne

Effective acoustic communication in the face of intense conspecific background noise constitutes a constant sensory challenge in chorusing and colonial species. An evolutionary approach suggests that behavioural and environmental constraints in these species should have shaped signal design and signalling behaviour to enable communication in noisy conditions. This could be attained both through the use of multicomponent signals and through short-term adjustments in the spatial separation of calling males. We investigated these two hypotheses in a chorusing anuran, the hylid Hyla arborea , through a series of phonotaxis experiments conducted within a six-speaker arena in a high background noise situation, by presenting females with male calls containing either single or multiple attractive call components, and by modifying distances between speakers. We found that female ability to discriminate attractive calls increased when several attractive call components were available, providing novel evidence that the use of multicomponent signals enhances communication in complex acoustic conditions. Signal discrimination in females also improved with speaker separation, demonstrating that within natural choruses, spatial unmasking conditioned by male density and spatial separation probably improves female discrimination of competing males. Implications of these results for the accuracy of mate choice within choruses are discussed.


2021 ◽  
Author(s):  
Yuichi Imanishi ◽  
Kazunari Nawa ◽  
Yoshiaki Tamura ◽  
Hiroshi Ikeda

Abstract One of the characteristic features of the gravity recordings produced by the superconducting gravimeter CT #036 at Ishigakijima, Japan, is that it indicates gravity increase when a typhoon (hurricane) approaches the island. Since we are trying to detect small gravity signals associated with the long-term slow slip events in this region, it is very important in the interpretation of the observed data whether such gravity changes are of natural or instrumental origin. In this paper, we investigate whether or not nonlinearity in the sensor of the superconducting gravimeter is responsible for this phenomenon. Here we take the same theoretical approach as taken by Imanishi et al. (2018) which investigated the effect of coupling between horizontal and vertical components of the gravity sensor in order to understand the noise caused by the movements of a nearby VLBI antenna. From theoretical and experimental approaches, we prove that the gravity increase observed by CT #036 at the times of high background noise level can not be explained by instrumental effects such as the nonlinearity in the vertical component or the coupling between horizontal and vertical components of the gravity sensor. This implies that the observed gravity increases are real gravity signals of natural origin.


2020 ◽  
Vol 13 (10) ◽  
pp. 5681-5695
Author(s):  
Bernd Kaifler ◽  
Dimitry Rempel ◽  
Philipp Roßi ◽  
Christian Büdenbender ◽  
Natalie Kaifler ◽  
...  

Abstract. The Balloon Lidar Experiment (BOLIDE) was the first high-power lidar flown and operated successfully on board a balloon platform. As part of the PMC Turbo payload, the instrument acquired high-resolution backscatter profiles of polar mesospheric clouds (PMCs) from an altitude of ∼ 38 km during its maiden ∼ 6 d flight from Esrange, Sweden, to northern Canada in July 2018. We describe the BOLIDE instrument and its development and report on the predicted and actual in-flight performance. Although the instrument suffered from excessively high background noise, we were able to detect PMCs with a volume backscatter coefficient as low as 0.6×10-10 m−1 sr−1 at a vertical resolution of 100 m and a time resolution of 30 s.


1971 ◽  
Vol 8 (3) ◽  
pp. 347-360 ◽  
Author(s):  
M. J. Berry ◽  
K. G. Barr

During the spring of 1967, a seismic refraction experiment was conducted from the SW tip of Prince Patrick Island in the Queen Elizabeth Islands of Arctic Canada to a point mid-way down the continental slope, some 220 km from the coast.It was found that seismic recording on sea ice was plagued by unusually high background noise levels which could be attributed to low frequency (below 1 Hz) oscillations of the ice pans and to the broad-band noise generated by frequent ice cracking. It was discovered, and is shown theoretically, that seismic wave propagating through a water layer (the ocean) and incident on the ice layer from below provide an exact π/2 phase shift between the horizontal and vertical components of surface motion. This fact can be used to advantage in digital processing.The interpretation shows a crustal model with depths to the M discontinuity of 28 ± 4 km at the coast, thinning to 15 ± 9 km at the end of the profile. The velocity of the mantle is measured as 8.05 ± 0.17 km/s. Mid-way down the continental slope there are 5.0 ± 1.63 km of sediments overlying material with a velocity of 5.36 ± 0.15 km/s. Material of a similar velocity, 5.72 ± 0.18 km/s, lies 2.7 ± 1.9 km beneath the surface material at the coast, where the surface layer has a velocity of 4.76 ± 0.4 km/s. It is concluded that the data support the hypothesis that the Canada Basin has an oceanic rather than a continental crust.


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